ci: consolidate platform pipelines and test prerequisites on macOS support

MeetingAssistant.Tests/SpeakerRecognitionFeatureSelectionTests.cs

@@ -1,7 +1,6 @@
 using MeetingAssistant.Speakers;
 using Microsoft.Data.Sqlite;
 using Microsoft.AspNetCore.Hosting;
-using Microsoft.AspNetCore.Mvc.Testing;
 using Microsoft.AspNetCore.TestHost;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
@@ -25,7 +24,7 @@ public sealed class SpeakerRecognitionFeatureSelectionTests
         Directory.CreateDirectory(directory);
         try
         {
-            await using var factory = new WebApplicationFactory<Program>()
+            await using var factory = new IsolatedApplicationFactory()
                 .WithWebHostBuilder(builder =>
                 {
                     builder.ConfigureAppConfiguration((_, configuration) =>