[web] remove platform_messages_integration test (#147654)

This functionality is already fully covered by https://github.com/flutter/engine/blob/main/lib/web_ui/test/engine/platform_views/message_handler_test.dart

This might help with flutter/flutter#146189 a little.

Author: yjbanov

dev/bots/suite_runners/run_web_tests.dart

@@ -142,11 +142,6 @@ class WebTestsSuite {
         ),
       ],
 
-      // This test doesn't do anything interesting w.r.t. rendering, so we don't run the full build mode x renderer matrix.
-      () => _runWebE2eTest('platform_messages_integration', buildMode: 'debug', renderer: 'canvaskit'),
-      () => _runWebE2eTest('platform_messages_integration', buildMode: 'profile', renderer: 'html'),
-      () => _runWebE2eTest('platform_messages_integration', buildMode: 'release', renderer: 'html'),
-
       // This test doesn't do anything interesting w.r.t. rendering, so we don't run the full build mode x renderer matrix.
       () => _runWebE2eTest('profile_diagnostics_integration', buildMode: 'debug', renderer: 'html'),
       () => _runWebE2eTest('profile_diagnostics_integration', buildMode: 'profile', renderer: 'canvaskit'),