[lib] Restart BaseAutoJoinCommunityHandler when FID changes

Summary:
This diff addresses [ENG-9539](https://linear.app/comm/issue/ENG-9539/restart-autojoincommunityhandler-after-fid-changes).

Depends on D13627

Test Plan: To be honest, I haven't tested this... I think the change is pretty predictable and safe

Reviewers: varun

Reviewed By: varun

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D13628

lib/components/base-auto-join-community-handler.react.js

@@ -79,7 +79,7 @@ function BaseAutoJoinCommunityHandler(props: Props): React.Node {
     React.useState<?CommunitiesToAutoJoin>();
 
   const prevCanQueryRef = React.useRef<?boolean>();
-  const canQuery = loggedIn;
+  const canQuery = loggedIn && !!fid;
 
   React.useEffect(() => {
     if (canQuery === prevCanQueryRef.current) {