When open multiple worktree, using `file_finder` to create a new file
shoud respect current focused worktree.
test case:
```
project:
   worktree A
        file1
   worktree B
        file2 <-  focused
```
when focused `file2`, `ctrl-p` toggle `file_finder` to create `file3`
should exists in worktreeB.


I try add test case for `CreateNew` in file_finder, but found not
worked, if you help me, I can try add this test case.

Release Notes:

- Fixed file finder selecting wrong worktree when creating a file