Fix the next step for a location request

An AI wrote a Flutter "find nearby" feature that called requestPermission(), ignored the result, and went straight to getCurrentPosition(). On a phone where location was already allowed, it worked. After a tester denied the prompt, or with location switched off, the feature hung or crashed. The fix turns the permission result into one next step.

An assistant wrote resolve_location_request(permission_status, service_enabled, has_shown_rationale). It is in the editor. It has a bug. Find it and fix it.

Input and output:

• permission_status: the status the permission API returned.
• service_enabled: location services are on at the operating system level.
• has_shown_rationale: the app has already explained once why it needs location.
• Return the next step: fetch, request_permission, show_rationale, open_app_settings, open_location_settings or unsupported.

Rules the tests check. Return the first that applies:

1. The status is not exactly one of notDetermined, denied, deniedForever, restricted, whileInUse or always, case included: unsupported.
2. deniedForever or restricted: open_app_settings, since the app can never ask again.
3. Location services are off: open_location_settings.
4. whileInUse or always: fetch. This is the only step that reads the position.
5. notDetermined: request_permission.
6. denied: request_permission if the rationale has been shown, otherwise show_rationale.