Fix the issue when running the unit tests (#18300)

* Fix the issue in unit tests.

- In the module we create a minimum runspace for PowerShell, and use it to parse the command line.
  The mini runspace contains the built-in core modules for PowerShell. We don't need them when we
  package and publish our module because the runtime will have them. That'll reduce the module size.
  So in the module project we exclude `contentfiles` when we referece Microsoft.PowerShell.SDK.
- The issue in the unit tests is that it doesn't find the built-in core module when we create the runspace.
  So we have a reference to Microsoft.PowerShell.SDK in the test project to include `contentfiles` to provide
  the built-in core modules. The unit tests can run successfully.

* Test

tools/Az.Tools.Predictor/Az.Tools.Predictor.Test/Az.Tools.Predictor.Test.csproj

@@ -24,6 +24,11 @@
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
     <ProjectReference Include="..\Az.Tools.Predictor\Az.Tools.Predictor.csproj" />
+    <!-- The test project doesn't reference to it directly. Az.Tools.Predictor has a reference to Microsoft.PowerShell.SDK.
+      - But it's excluding content files to reduce the size of the module. The content files are not needed since they're in the runtime (PowerShell)
+      - The content files are needed to set up the runspace to parse the command line. So we need to include them when we run the unit tests.
+      -->
+    <PackageReference Include="Microsoft.PowerShell.SDK" Version="7.2.0" />
   </ItemGroup>
 
   <ItemGroup>

tools/Az.Tools.Predictor/Az.Tools.Predictor/Az.Tools.Predictor.csproj

@@ -24,7 +24,6 @@ For more information on Az Predictor, please visit the following: https://aka.ms
     <PackageReference Include="Microsoft.ApplicationInsights" Version="2.18.0" />
     <PackageReference Include="Microsoft.Azure.PowerShell.Common.Share" Version="1.3.45-preview" />
     <PackageReference Include="Microsoft.PowerShell.SDK" Version="7.2.0">
-      <ExcludeAssets>contentFiles</ExcludeAssets>
     </PackageReference>
     <PackageReference Include="System.Management.Automation" Version="7.2.0">
       <ExcludeAssets>contentFiles</ExcludeAssets>