chore: flatten namespace hierarchy

[MaggieKimani1]

Flattens namespaces to align with single top-level namespace
Fiixes #2367

[darrelmiller]

Sorry, I missed a few namespaces in the list I created in the issue. We should also remove

Microsoft.OpenApi.Extensions
Microsoft.OpenApi.Services
Microsoft.OpenApi.Validations
Microsoft.OpenApi.Writers

The Extensions one is especially important because the discovery of extension methods is hard when they are in a different namespace.

[MaggieKimani1]

Sorry, I missed a few namespaces in the list I created in the issue. We should also remove

Microsoft.OpenApi.Extensions Microsoft.OpenApi.Services Microsoft.OpenApi.Validations Microsoft.OpenApi.Writers

The Extensions one is especially important because the discovery of extension methods is hard when they are in a different namespace.

What about Microsoft.OpenApi.Expressions?

[sonarqubecloud]

Quality Gate failed

Failed conditions
66.7% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud