refactor: remove generic 'Enum' endpoints #605

[heisdinesh]

Change(s)

• Exclude generic EnumRouter instances from router registration to remove endpoints like /keywords and /pysical_entities.
• Retain TaxonomyRouter endpoints and internal NamedRelation normalization logic.
• Rename test_license_router.py to test_enum_routers.py and add verification for 404 responses on removed endpoints.

Change Type: Removed

Change Category: Interface

Changelog Entry:
Removed generic enum endpoints (e.g., /keywords, /pysical_entities) that do not use Taxonomies.

These endpoints were previously used to normalize string data, but this is now handled "under the hood" during resource creation/synchronization. Taxonomies and their corresponding endpoints remain available.

How to Test

1. Run the specific tests for enum routers:

   pytest src/tests/routers/enum_routers/test_enum_routers.py

2. Run the full test suite to ensure no regressions:

   pytest src/tests

3. Manually verify that GET /keywords returns 404 Not Found and GET /news_categories (a taxonomy) returns 200 OK.

Checklist

• Tests have been added or updated to reflect the changes, or their absence is explicitly explained.
• Documentation has been added or updated to reflect the changes, or their absence is explicitly explained.
• A self-review has been conducted checking:
  • No unintended changes have been committed.
  • The changes in isolation seem reasonable.
  • Anything that may be odd or unintuitive is provided with a GitHub comment explaining it.
• All CI checks pass before pinging a reviewer, or provide an explanation if they do not.
• The PR title matches the changelog entry's one-line description.

Related Issues

Closes #605

[heisdinesh]

Hey @PGijsbers could you review this PR.