Remove delay in /api/ask-streaming endpoint response

Eliminated the 50ms delay in the asynchronous streaming response
logic of the /api/ask-streaming endpoint by removing the line
`await Task.Delay(50);`. This change improves the response time
by removing unnecessary latency after each delta in the response
stream.

SqlDatabaseVectorSearch/Program.cs

@@ -151,7 +151,6 @@ app.MapPost("/api/ask-streaming", (Question question, VectorSearchService vector
         await foreach (var delta in responseStream)
         {
             yield return delta;
-            await Task.Delay(50);
         }
     }