Update Dart SDK to 5788b6a (#39952)

Author: itsjustkevin

DEPS

@@ -48,7 +48,7 @@ vars = {
   # Dart is: https://github.com/dart-lang/sdk/blob/main/DEPS
   # You can use //tools/dart/create_updated_flutter_deps.py to produce
   # updated revision list of existing dependencies.
-  'dart_revision': 'e46b4f59490230778e907bde2eedb06b062d31be',
+  'dart_revision': '5788b6a2ba56fe64e86838f6520d223a0127a309',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py