[feature] improve test coverage for `tags` and `notification test`

Based on my analysis of the codebase, here are some endpoints that appear to have less test coverage:

1. Several conditions blueprint endpoints:
- /conditions//verify-condition-single-rule route **(fixed)**
2. Settings blueprint endpoints:
- /settings/reset-api-key
3. Many of the tag-related endpoints:
- /tags/mute/
- /tags/unlink/
- /tags/edit/ (GET and POST) (sort of related https://github.com/dgtlmoon/changedetection.io/issues/2942 )
4. Price data follower endpoints:
- Appears to have less comprehensive tests
5. The /api/share-url endpoint
6. Notification testing endpoints:
- /notification/send-test/

Start by reviewing the existing tests and handlers for /tags/mute/, /tags/unlink/, /tags/edit/, /settings/reset-api-key, /api/share-url, and /notification/send-test/. Add coverage for the untested behavior across the selected endpoints, including GET and POST for tag editing, and confirm the test suite passes.

Written by the indexing model from the issue text.