recent_topics: Don't restore filters for spectators.
recent_topics: Don't restore filters for spectators.

This fixes the bug where spectators can have filters selected
in recent topics if a logged in user has selected filters in the
same browser.

Log in, select a filter and log out to reproduce this.

rht/zulip,zulip/zulip,rht/zulip,andersk/zulip,andersk/zulip,rht/zulip,zulip/zulip,rht/zulip,zulip/zulip,andersk/zulip,rht/zulip,rht/zulip,andersk/zulip,andersk/zulip,zulip/zulip,andersk/zulip,rht/zulip,zulip/zulip,zulip/zulip,andersk/zulip,zulip/zulip