Roll Flutter from 919d20511cf6 to adafd66d9cc7 (5 revisions) (#4876)

diff --git a/.ci/flutter_master.version b/.ci/flutter_master.version
index e152d93..c2fc9dc 100644
--- a/.ci/flutter_master.version
+++ b/.ci/flutter_master.version
@@ -1 +1 @@
-919d20511cf667d1dc0b8b4bac06b202b60af641
+adafd66d9cc7796214404c8117395e207bf23d01