`dotnet workload restore` fails on macOS when a project uses an SDK that is not yet in the package cache

### Describe the bug

When `dotnet workload restore` is run in a directory containing a project that requires an SDK to be restored, it fails.

Interestingly, it only fails on my macOS agent. Linux and Windows appear to have no problem with it.

### To Reproduce

Create a directory with the following `dirs.proj` in it:

```xml

```

I also had this `global.json` in place:

```json
{
"sdk": {
"version": "8.0.400",
"rollForward": "patch",
"allowPrerelease": false
},
"msbuild-sdks": {
"Microsoft.Build.Traversal": "4.1.0"
}
}
```

Set the environment variable `NUGET_PACKAGES` to an empty or non-existent directory.

Run `dotnet workload restore`

### Expected

A successful workload restore

### Actual

This failure:

```
Unhandled exception: Microsoft.Build.Exceptions.InvalidProjectFileException: The SDK 'Microsoft.Build.Traversal' specified could not be found. /Users/buildagent/myagent/_work/1/s/azure-pipelines/dirs.proj
at Microsoft.Build.Shared.ProjectErrorUtilities.ThrowInvalidProject(String errorSubCategoryResourceName, IElementLocation elementLocation, String resourceName, Object[] args)
at Microsoft.Build.Shared.ProjectErrorUtilities.ThrowInvalidProject[T1](IElementLocation elementLocation, String resourceName, T1 arg0)
at Microsoft.Build.Evaluation.Evaluator`4.ExpandAndLoadImportsFromUnescapedImportExpressionConditioned(String directoryOfImportingFile, ProjectImportElement importElement, List`1& projects, SdkResult& sdkResult)
at Microsoft.Build.Evaluation.Evaluator`4.ExpandAndLoadImports(String directoryOfImportingFile, ProjectImportElement importElement, SdkResult& sdkResult)
at Microsoft.Build.Evaluation.Evaluator`4.EvaluateImportElement(String directoryOfImportingFile, ProjectImportElement importElement)
at Microsoft.Build.Evaluation.Evaluator`4.PerformDepthFirstPass(ProjectRootElement currentProjectOrImport)
at Microsoft.Build.Evaluation.Evaluator`4.Evaluate()
at Microsoft.Build.Evaluation.Evaluator`4.Evaluate(IEvaluatorData`4 data, Project project, ProjectRootElement root, ProjectLoadSettings loadSettings, Int32 maxNodeCount, PropertyDictionary`1 environmentProperties, ILoggingService loggingService, IItemFactory`2 itemFactory, IToolsetProvider toolsetProvider, IDirectoryCacheFactory directoryCacheFactory, ProjectRootElementCacheBase projectRootElementCache, BuildEventContext buildEventContext, ISdkResolverService sdkResolverService, Int32 submissionId, EvaluationContext evaluationContext, Boolean interactive)
at Microsoft.Build.Execution.ProjectInstance.Initialize(ProjectRootElement xml, IDictionary`2 globalProperties, String explicitToolsVersion, String explicitSubToolsetVersion, Int32 visualStudioVersionFromSolution, BuildParameters buildParameters, ILoggingService loggingService, BuildEventContext buildEventContext, ISdkResolverService sdkResolverService, Int32 submissionId, Nullable`1 projectLoadSettings, EvaluationContext evaluationContext, IDirectoryCacheFactory directoryCacheFactory)
at Microsoft.Build.Execution.ProjectInstance..ctor(String projectFile, IDictionary`2 globalProperties, String toolsVersion, String subToolsetVersion, ProjectCollection projectCollection, Nullable`1 projectLoadSettings, EvaluationContext evaluationContext, IDirectoryCacheFactory directoryCacheFactory, Boolean interactive)
at Microsoft.Build.Execution.ProjectInstance..ctor(String projectFile, IDictionary`2 globalProperties, String toolsVersion)
at Microsoft.DotNet.Workloads.Workload.Restore.WorkloadRestoreCommand.RunTargetToGetWorkloadIds(IEnumerable`1 allProjects)
at Microsoft.DotNet.Workloads.Workload.Restore.WorkloadRestoreCommand.Execute()
at System.CommandLine.Invocation.InvocationPipeline.Invoke(ParseResult parseResult)
at Microsoft.DotNet.Cli.Program.ProcessArgs(String[] args, TimeSpan startupTime, ITelemetry telemetryClient)
```

### Workaround

Running `dotnet restore` before `dotnet workload restore` avoids the problem.