Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] ~Unsafe blocks (if any) have justifying comments~
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Followup to #47531 to use the gpui feature in Zed. This just plumbs the
"system bell" feature into the terminal, behind a new setting (enabled
by default, like most other terminal applications).

Closes #5303
Relates to
https://github.com/zed-industries/zed/issues/40826#issuecomment-3684556858

Release Notes:

- Added audible BEL to Terminal; can be enabled by setting
`terminal.bell` to `"system"`.

---------

Co-authored-by: Matt Van Horn <455140+mvanhorn@users.noreply.github.com>
Co-authored-by: Ben Kunkle <Ben.kunkle@gmail.com>