Fix: community badges

[bwindels]

Don't assume a user has joined all the rooms in a community

[ara4n]

personally i prefer an explicit check (e.g. !== null or !== undefined) than !!r but otherwise lgtm

[bwindels]

personally i prefer an explicit check (e.g. !== null or !== undefined) than !!r but otherwise lgtm

Checking for both just in case getRoom starts returning undefined instead of null at some point in the future.