[flutter_tool] add enable-embedder-api flag (#121895)

[flutter_tool] add enable-embedder-api flag
https://dart.googlesource.com/external/github.com/flutter/flutter/+/b81b1e28a33ef7f82cf0391171ad8f74ad858fe8

DEPS

diff --git a/DEPS b/DEPS
index 9f433f2..402f9a2 100644
--- a/DEPS
+++ b/DEPS
@@ -246,7 +246,7 @@
 
   'engine/src/third_party/dart': Var('dart_git') + '/sdk' + '@' + '08d9d8586a901d34db3c1100c85a0fe5578166a9',
 
-  'flutter': Var('flutter_git') + '/mirrors/flutter' + '@' + 'd55130479a338e223c98d2b77fac891b2f711db6',
+  'flutter': Var('flutter_git') + '/mirrors/flutter' + '@' + 'b81b1e28a33ef7f82cf0391171ad8f74ad858fe8',
 
    # Fuchsia compatibility
    #

commits.json

diff --git a/commits.json b/commits.json
index dd2ee34..2bf04a6 100644
--- a/commits.json
+++ b/commits.json
@@ -1,5 +1,5 @@
 {
   "engine/src/flutter":"55b66314072b33101ef0dc8f00cc07ebe75d6b1d",
   "engine/src/third_party/dart":"08d9d8586a901d34db3c1100c85a0fe5578166a9",
-  "flutter":"d55130479a338e223c98d2b77fac891b2f711db6"
+  "flutter":"b81b1e28a33ef7f82cf0391171ad8f74ad858fe8"
 }
\ No newline at end of file