file_finder: Fix crash in new_path_prompt (#16991)
CharlesChen0823
created
Closes #16919
repro step:
- add two worktree
- modify settings `"use_system_path_prompts" : false`
- `ctrl-n` create new file, typing any chars.
- `ctrl-s` save file
- typing any char, crashed.
Release Notes:
- Fixed crashed when setting `"use_system_path_prompts": false` or in
remote project with two or more worktree.