Fix: Allow --version option with workload restore

[Copilot]

dotnet workload restore --version <version> fails with error "Cannot use the --skip-manifest-update and --sdk-version options together" even though these options should be compatible for restore operations.

Root Cause

workload restore internally calls WorkloadInstallCommand with skipManifestUpdate: true to avoid duplicate manifest updates. The validation logic rejected this combination without accounting for the restore context where users legitimately specify --version while the implementation uses skipManifestUpdate.

Changes

• WorkloadInstallCommand.cs: Added !IsRunningRestore guard to version/skip-manifest validation (line 158), matching the existing pattern for global.json validation (line 165)
• GivenDotnetWorkloadRestore.cs: Added test verifying --version no longer triggers the conflict error

Example

# Previously failed with validation error
dotnet workload restore --version 9.0.100

# Now proceeds to install specified workload version

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Can't Restore Workloads with Version</issue_title>
<issue_description>### Describe the bug
dotnet workload restore --version breaks if you give it a version (e.g. 9.0.305) or as the --help text suggests, a workload and a version (e.g. ios@9.0.305).

To Reproduce

1. mkdir test
2. cd test
3. dotnet new console
4. dotnet workload restore --version 9.0.305

Exceptions (if any)

dotnet exits with code 1 and this message:

Cannot use the --skip-manifest-update and --sdk-version options together.  Remove one of the options.

Further technical details

details of dotnet --info

.NET SDK: Version: 9.0.305 Commit: 3fc74f3 Workload version: 9.0.305 MSBuild version: 17.14.21+8929ca9e3

Runtime Environment:
OS Name: Windows
OS Version: 10.0.19045
OS Platform: Windows
RID: win-x64
Base Path: C:\Program Files\dotnet\sdk\9.0.305\

.NET workloads installed:
[android]
Installation Source: SDK 9.0.300, VS 17.14.36310.24
Manifest Version: 35.0.101/9.0.100
Manifest Path: C:\Program Files\dotnet\sdk-manifests\9.0.100\microsoft.net.sdk.android\35.0.101\WorkloadManifest.json
Install Type: Msi

[ios]
Installation Source: SDK 9.0.300, VS 17.14.36310.24
Manifest Version: 18.5.9219/9.0.100
Manifest Path: C:\Program Files\dotnet\sdk-manifests\9.0.100\microsoft.net.sdk.ios\18.5.9219\WorkloadManifest.json
Install Type: Msi

[maccatalyst]
Installation Source: SDK 9.0.300, VS 17.14.36310.24
Manifest Version: 18.5.9219/9.0.100
Manifest Path: C:\Program Files\dotnet\sdk-manifests\9.0.100\microsoft.net.sdk.maccatalyst\18.5.9219\WorkloadManifest.json
Install Type: Msi

[maui-windows]
Installation Source: SDK 9.0.300, VS 17.14.36310.24
Manifest Version: 9.0.82/9.0.100
Manifest Path: C:\Program Files\dotnet\sdk-manifests\9.0.100\microsoft.net.sdk.maui\9.0.82\WorkloadManifest.json
Install Type: Msi

Configured to use workload sets when installing new manifests.

Host:
Version: 9.0.9
Architecture: x64
Commit: 893c2ebbd4

.NET SDKs installed:
2.1.526 [C:\Program Files\dotnet\sdk]
5.0.300 [C:\Program Files\dotnet\sdk]
6.0.101 [C:\Program Files\dotnet\sdk]
6.0.201 [C:\Program Files\dotnet\sdk]
7.0.410 [C:\Program Files\dotnet\sdk]
8.0.413 [C:\Program Files\dotnet\sdk]
9.0.302 [C:\Program Files\dotnet\sdk]
9.0.305 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.All 2.1.24 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.26 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.27 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.28 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.24 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.26 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.27 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.28 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 6.0.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 6.0.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.18 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.19 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 9.0.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 9.0.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.1.24 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.NETC...

• Fixes Can't Restore Workloads with Version #51259

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