Roll Flutter from d1a4e1a295b4 to 9d96c7b8be2c (2 revisions) (#2401)

diff --git a/.ci/flutter_master.version b/.ci/flutter_master.version
index 96336bd..655a54c 100644
--- a/.ci/flutter_master.version
+++ b/.ci/flutter_master.version
@@ -1 +1 @@
-d1a4e1a295b4df49de86030581c5350fa9efb929
+9d96c7b8be2c71c3c243bbdf53df1dbd3010d027