Install .NET 8 and 9 runtimes

Ensure the .NET 8 and 9 runtimes are present.

Author: martincostello

.github/workflows/Component.BuildTest.yml

@@ -58,6 +58,7 @@ jobs:
       with:
         dotnet-version: |
           8.0.x
+          9.0.x
 
     - name: Setup .NET
       uses: actions/setup-dotnet@67a3573c9a986a3f9c594539f4ab511d57bb3ce9 # v4.3.1