RTFDB-4842: Improve user input handling in "mapbox-gl-geocoder"

[pahuta]

• Remove numeric-range bound on coordinate detection regex so it matches how the Geocoding v5 API itself detects coordinate-shaped queries, fixing forward/reverse misclassification (422 errors) for out-of-range coordinate-like input
• Require a comma (with optional surrounding whitespace) as the coordinate separator so whitespace-only separated numbers are still treated as a forward query
• Deduplicate the coordinate regex in the forward-request branch, reusing the shared utils.REVERSE_GEOCODE_COORD_RGX
• Add corresponding test cases and changelog entry

Since code-scanning found an issue https://github.com/mapbox/mapbox-gl-geocoder/security/code-scanning/7, I also:

• Reject search input over 256 characters (mirrors the Geocoding v5 API's own limit) with a dedicated "search is too long" error instead of sending it to the API.
• Centralize attribution-hiding in _renderMessage() so it's consistently hidden for every error/no-results message.
• Fix two independent races with the suggestions library's own native keyup/paste listeners on the input element that could redraw the list from stale/empty data and wipe out a just-rendered message — most visibly, pasting an over-limit value directly (via keyboard shortcut) silently failed to show the "too long" error.

https://mapbox.atlassian.net/browse/RTFDB-4842

• briefly describe the changes in this PR
• write tests for all new functionality
• run npm run docs and commit changes to API.md
• update CHANGELOG.md with changes under main heading before merging

Previous behavior vs new behavior:

reverse.mp4

Add checking search input length before sending requests to Geocoding v5 API.

Previous behavior

old.mp4

New behavior

new.mp4