[devicelab] explicitly enable vulkan validation in test. (#147382)

Part of https://github.com/flutter/flutter/issues/142659

this test expects validation layers on, so we need to explicitly enable
them before we can turn them off by default.
https://dart.googlesource.com/external/github.com/flutter/flutter/+/4e16e67946fb901991a2c622bcc2981107541d62
diff --git a/DEPS b/DEPS
index e920dd0..0d8cde7 100644
--- a/DEPS
+++ b/DEPS
@@ -295,7 +295,7 @@
 
   'engine/src/flutter/third_party/dart': Var('dart_git') + '/sdk' + '@' + '5c3cad7a339af562066d7797885a65314c090cae',
 
-  'flutter': Var('flutter_git') + '/mirrors/flutter' + '@' + 'ab715b1c7661bf80800abc847dac1045f45658b7',
+  'flutter': Var('flutter_git') + '/mirrors/flutter' + '@' + '4e16e67946fb901991a2c622bcc2981107541d62',
 
   'engine/src/flutter/third_party/depot_tools':
   Var('chromium_git') + '/chromium/tools/depot_tools.git' + '@' + '580b4ff3f5cd0dcaa2eacda28cefe0f45320e8f7',
diff --git a/commits.json b/commits.json
index 89f57b2..1853f4e 100644
--- a/commits.json
+++ b/commits.json
@@ -1,5 +1,5 @@
 {
   "engine/src/flutter":"0f31cba4420549f53b0a643d2e4a9e24c2e77d63",
   "engine/src/flutter/third_party/dart":"5c3cad7a339af562066d7797885a65314c090cae",
-  "flutter":"ab715b1c7661bf80800abc847dac1045f45658b7"
+  "flutter":"4e16e67946fb901991a2c622bcc2981107541d62"
 }
\ No newline at end of file