Revert "Simplify discussion/tag permission logic"
Revert "Simplify discussion/tag permission logic"

This reverts commit d43c876d2fcaaefd641d9c21b8d157c46f686723.

Turns out that there was a good reason for the original logic... the case of per-tag moderators.

flarum/flarum-ext-tags,flarum/flarum-ext-tags,Luceos/flarum-tags,Luceos/flarum-tags