Bump dart_bridge_version to 1.4.1 (#26)

dart-bridge 1.4.1 adds armeabi-v7a binaries for Python 3.13/3.14. Bump the
manifest so the next date-keyed release advertises it to serious_python / flet.

Author: FeodorFitsner

manifest.json

@@ -1,6 +1,6 @@
 {
   "default_python_version": "3.14",
-  "dart_bridge_version": "1.4.0",
+  "dart_bridge_version": "1.4.1",
   "pythons": {
     "3.12": {
       "full_version": "3.12.13",