fix(reddit): fix availibility check

[spifory]

Changes the text to check for on Reddit as 'Sorry there aren't any communities on Reddit with that name.' is an old message (which can be found at https://new.reddit.com/r/invalidsubreddit), the current message is 'Community not found', as seen on https://www.reddit.com/r/invalidsubreddit/

[vercel[bot]]

@spifory is attempting to deploy a commit to the Yasuaki Uechi's projects Team on Vercel.

A member of the Team first needs to authorize it.