Validate scopes in OpenApiDocumentProvider tests and fix scope (#58307)

* Validate scopes in OpenApiDocumentProvider tests and fix scope

* Use IOptionsMonitor to resolve OpenApiOptions

Author: captainsafia

src/OpenApi/src/Services/OpenApiDocumentProvider.cs

@@ -25,8 +25,8 @@ internal sealed class OpenApiDocumentProvider(IServiceProvider serviceProvider)
     /// <param name="writer">A text writer associated with the document to write to.</param>
     public async Task GenerateAsync(string documentName, TextWriter writer)
     {
-        var optionsSnapshot = serviceProvider.GetRequiredService<IOptionsSnapshot<OpenApiOptions>>();
-        var namedOption = optionsSnapshot.Get(documentName);
+        var options = serviceProvider.GetRequiredService<IOptionsMonitor<OpenApiOptions>>();
+        var namedOption = options.Get(documentName);
         var resolvedOpenApiVersion = namedOption.OpenApiVersion;
         await GenerateAsync(documentName, writer, resolvedOpenApiVersion);
     }

src/OpenApi/test/Microsoft.AspNetCore.OpenApi.Tests/Services/OpenApiDocumentProviderTests.cs

@@ -68,7 +68,7 @@ private static IServiceProvider CreateServiceProvider(string[] documentNames)
         {
             serviceCollection.AddOpenApi(documentName);
         }
-        var serviceProvider = serviceCollection.BuildServiceProvider();
+        var serviceProvider = serviceCollection.BuildServiceProvider(validateScopes: true);
         return serviceProvider;
     }
 }