Improve normalization and validation of member JIDs
It seems in some cases JIDs leak through to room affiliations that have not been normalized.
Related downstream issues this can cause:
I'd like to make some small improvements to the way member JIDs are read from the API data, to ensure they are always normalized and verified before using them for any purpose, instead of attempting to normalize them each time we use them.
This normalization is already done for JIDs of circles and users, but not when processing JIDs of circle members.