Our pipelines do not cover sample project compilation.

Currently in azure-sdk-for-net main the Azure.ResourceManager.Samples.csproj project is broken and won't compile. This was not caught during CI because in the build step we run `dotnet pack` which will ignore the sample csproj, and in the test step we run `dotnet test` which again will ignore the sample csproj.

We should add an extra step somewhere to check if there is a sample project and if there is build it. This is important since our samples in our readme are created from this project and so if it doesn't build we are giving faulty samples to our customers.

Related issue where we found this https://github.com/Azure/autorest.csharp/issues/5214

Start by locating the Azure pipeline steps that run dotnet pack and dotnet test, then inspect how sample projects are identified. Add a CI check that builds Azure.ResourceManager.Samples.csproj when present, and verify that the pipeline catches a sample project compilation failure.

Written by the indexing model from the issue text.