Handle FileNotFoundError

I'm guessing watchdog's behaviour changed in an update, as the error
thrown when the watched directory doesn't exist is now
"FileNotFoundError" instead of "NotADirectoryError". It'll handle either
one now.

jellyfin_accounts/pw_reset.py

@@ -19,7 +19,8 @@ class Watcher:
         self.observer.schedule(event_handler, self.dir, recursive=True)
         try:
             self.observer.start()
-        except NotADirectoryError:
+        except (NotADirectoryError,
+                FileNotFoundError):
             log.error(f"Directory {self.dir} does not exist")
         try:
             while True: