Fix the `OSError: [Errno 30] Read-only file system` problem in newer versions of Anki

[alicia-lyu]

credit to https://github.com/AnkiStudio, https://github.com/sth2018/FastWordQuery/issues/259

Fix the OSError: [Errno 30] Read-only file system: '_fastwqcfg.json' problem, when modifying the configurations in newer versions of Anki, by changing the root to a path with w permission.

Tested on MacBook Pro M1 Ventura 13