Disable Http3 LargeSingleHeader_ThrowsException Test (#91930)

Disabling HTTP/3 test `LargeSingleHeader_ThrowsException` against #74896 because it's happening quite often until we're back to investigate it.

Related to #91757

src/libraries/System.Net.Http/tests/FunctionalTests/SocketsHttpHandlerTest.cs

@@ -1633,6 +1633,7 @@ public sealed class SocketsHttpHandler_HttpClientHandler_MaxResponseHeadersLengt
         protected override Version UseVersion => HttpVersion.Version20;
     }
 
+    [ActiveIssue("https://github.com/dotnet/runtime/issues/74896")]
     [ConditionalClass(typeof(HttpClientHandlerTestBase), nameof(IsQuicSupported))]
     public sealed class SocketsHttpHandler_HttpClientHandler_MaxResponseHeadersLength_Http3 : SocketsHttpHandler_HttpClientHandler_MaxResponseHeadersLength
     {