Roll Flutter from 7714a8d034ad to 5816d20b86b9 (23 revisions) (#6443)

diff --git a/.ci/flutter_master.version b/.ci/flutter_master.version
index 1da87c3..c78f850 100644
--- a/.ci/flutter_master.version
+++ b/.ci/flutter_master.version
@@ -1 +1 @@
-7714a8d034ad418bcfcf421e12f45f121c356948
+5816d20b86b95205c40921fa91ee3434b9c97ac6