hotfix: Proper clearing of the ID<->URI mappings

[Voltra]

When removing the last entries of any of the two ID<->URI mappings, the cached value used to become an empty array, which in turn broke all read operations from said mapping and thus most of the features related to routing.

The bug could only occur in three situations:

• With the hook-to-commands config option set to true, when calling any of the clear kind of 1st-party artisan commands (note that some commands like route:cache also silently call route:clear first, so these count as well)
• When installing the package if a script call any of said 1st-party artisan commands (since the option is currently defaulting to true)
• When deleting the last existing page

This PR addresses this issue by removing the mapping from the cache instead of caching an empty mapping. This effectively clears out the mapping and properly invalidates caches.

Fixes #198

[what-the-diff]

PR Summary

• Improved Cache Handling:
  The updates in the methods replaceIdToUriMapping and replaceUriToIdMapping enable better management of our application's memory cache. By checking if any new mapping is empty before replacing, we avoid unnecessary use of memory space. This results in increased efficiency and better performance of our app.