Fixes flaky HTTP/3 test (#29999)

Author: jkotalik

src/Servers/Kestrel/test/InMemory.FunctionalTests/Http3/Http3StreamTests.cs

@@ -277,7 +277,6 @@ public async Task MissingAuthority_200Status()
                 new KeyValuePair<string, string>(HeaderNames.Path, "/"),
                 new KeyValuePair<string, string>(HeaderNames.Scheme, "http"),
             };
-            await InitializeConnectionAsync(_noopApplication);
 
             var requestStream = await InitializeConnectionAndStreamsAsync(_noopApplication);