Skip `/api/update-task-status` on Devicelab (#165614)

Mitigates https://github.com/flutter/flutter/issues/165610.

If this works, we can likely not only fix the tree status, but delete
code from Cocoon (and dev/devicelab). Yay!
https://dart.googlesource.com/external/github.com/flutter/flutter/+/55f257e39ea481602030632ec115b9a8ba60611d

DEPS

diff --git a/DEPS b/DEPS
index 53314a0..c041e39 100644
--- a/DEPS
+++ b/DEPS
@@ -240,7 +240,7 @@
 deps = {
   'flutter/engine/src/flutter/third_party/dart': Var('dart_git') + '/sdk' + '@' + 'a90bb090b0e199830e7606a4af4a51d450717360',
 
-  'flutter': Var('flutter_git') + '/mirrors/flutter' + '@' + 'cab4fe33c3524a7e07771af4e4ad37258776769b',
+  'flutter': Var('flutter_git') + '/mirrors/flutter' + '@' + '55f257e39ea481602030632ec115b9a8ba60611d',
 
   'flutter/engine/src/flutter/third_party/depot_tools':
   Var('chromium_git') + '/chromium/tools/depot_tools.git' + '@' + '580b4ff3f5cd0dcaa2eacda28cefe0f45320e8f7',

commits.json

diff --git a/commits.json b/commits.json
index 18bfca3..f8fb774 100644
--- a/commits.json
+++ b/commits.json
@@ -1,4 +1,4 @@
 {
-  "flutter":"cab4fe33c3524a7e07771af4e4ad37258776769b",
+  "flutter":"55f257e39ea481602030632ec115b9a8ba60611d",
   "flutter/engine/src/flutter/third_party/dart":"a90bb090b0e199830e7606a4af4a51d450717360"
 }
\ No newline at end of file