Pinning .NET version to 6.0.0 as it's not available on Ubuntu 2404 ru…

…nners

.github/workflows/build-and-test.yml

@@ -19,6 +19,7 @@ jobs:
       build-configuration: Debug
       build-enable-nuget-caching: 'true'
       build-enable-npm-caching: 'true'
+      dotnet-version: 6.0.0
 
   build-and-test-standard-runners:
     if: github.ref_name == github.event.repository.default_branch
@@ -28,6 +29,7 @@ jobs:
       parent-job-name: 'root-solution-standard-runners'
       timeout-minutes: 30
       build-configuration: Debug
+      dotnet-version: 6.0.0
 
   build-and-test-nuget-test:
     name: Build and Test - NuGetTest solution
@@ -36,6 +38,7 @@ jobs:
       parent-job-name: 'nuget-solution'
       build-directory: NuGetTest
       timeout-minutes: 10
+      dotnet-version: 6.0.0
 
   post-pull-request-checks-automation:
     name: Post Pull Request Checks Automation