Bug 2072313 - Accept query-string params on Reminders add

[Xzzz]

Summary

Reminders.pm's add() only read parameters from the JSON POST body. Adds the query-string merge that the REST docs promise, reusing the same merge_request_params helper as bugs 2065171/2065173/2072305.

Depends on 2072305 per the bug dependency (both introduce the same shared helper; will collapse to one copy once either merges).

Changes

• Reuse Bugzilla::WebService::Util::merge_request_params (see 2072305)
• Reminders.pm add(): query string + JSON body merge instead of JSON-body-only
• qa/t/rest_reminders.t: cover query-string-only reminder creation

Side effect on bug 2072318: removes the try/catch this change replaces, which included the return inside catch that bug 2072318 was filed against (it never actually aborted add() on malformed JSON). That code no longer exists after this change, so 2072318 is resolved here rather than needing its own patch.

Test plan

• POST /rest/reminder with bug_id/note/reminder_ts entirely in the query string, no JSON body
• Existing qa/t/rest_reminders.t cases unaffected

References

• Bugzilla link: 2072313
• Depends on 2072305
• Resolves 2072318 as a side effect