Exclude gen.dart from analyzer checks

Added lib/src/gen.dart to the analyzer exclude list in analysis_options.yaml to prevent analysis of generated code.

Author: FeodorFitsner

src/serious_python_android/analysis_options.yaml

@@ -1,4 +1,8 @@
 include: package:flutter_lints/flutter.yaml
 
+analyzer:
+  exclude:
+    - lib/src/gen.dart
+
 # Additional information about this file can be found at
 # https://dart.dev/guides/language/analysis-options