feat(alert-channel-integrations): Jira add `wontFixResolution` UI Option (#12765)

#### Description

- Adds a **Won't-fix resolution** input to the Jira channel form
(Advanced section), with a help line explaining what it does. The
backend already supported `wont_fix_resolution`; it was API-only until
now.
- When set (e.g. `Won't Do`), a Jira issue resolved with that resolution
is not reopened when the alert fires again; a new issue is created
instead. Optional; empty keeps the current behavior.
- Editing a channel now preserves an API-set `wont_fix_resolution` on
re-save (it was silently dropped before).

#### Screenshots / Screen Recordings

<img width="1441" height="110" alt="Screenshot 2026-09-03 at 4 10 12 PM"
src="https://github.com/user-attachments/assets/fcefa36d-1f41-4bac-acf9-334356e52267"
/>