package/flutter-engine: bump version to 3.16.5

Flutter 3.16 includes 1,954 commits and improvements.

Flutter 3.16.0 also sets Material 3 as the default visual style for
applications.

A brief changelog can be found here:
https://docs.flutter.dev/release/release-notes/release-notes-3.16.0

A full changelog is provided below, which is provided at the end of the
brief changelog page found above:
https://github.com/flutter/engine/compare/3.13.0%E2%80%A63.16.0-0.5.pre

Signed-off-by: Adam Duskett <adam.duskett@amarulasolutions.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/flutter-engine/flutter-engine.mk

@@ -21,7 +21,7 @@
 #
 # There is no hash provided, as the gn binary (used for configuration) relies
 # on the .git directories. As such, a reproducible tarball is not possible.
-FLUTTER_ENGINE_VERSION = 3.13.9
+FLUTTER_ENGINE_VERSION = 3.16.5
 
 # There is nothing for Buildroot to download. This is handled by gclient.
 FLUTTER_ENGINE_SITE =