chore: Excl. gen. files from analysis_options.yaml

This commit updates the `analysis_options.yaml` file to exclude generated files from analysis. This is done by adding the `analyzer.exclude` option with the pattern `lib/**/*.*.dart`.

This change is necessary because generated files often contain code that does not adhere to the project's linting rules. Excluding them from analysis prevents unnecessary warnings and errors.

Author: xsahil03x

sample_app/analysis_options.yaml

@@ -1,5 +1,11 @@
 include: ../analysis_options.yaml
 
+analyzer:
+  # TODO: not working if added on the root analysis file
+  exclude:
+    # exclude all the generated files
+    - lib/**/*.*.dart
+
 linter:
   rules:
     cascade_invocations: false