The script was failing with newer pygobject versions because the
__enum_values__ attribute has been removed. Updated to use proper
introspection by:
- Getting enum type from property default value
- Using enum_class.values for the first enum value (index 0)
- Creating other enum values with enum_type(i) constructor
- Extracting name and nick from enum values properly
Also fixed ruff linting issues:
- Removed unused imports and variables
- Used specific exception types instead of bare except
- Added noqa comment for gi import ordering
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5987>
