priv and group member fix
priv and group member fix

before pushing mention notification to users filter the uids down to who can read that category
also fixed the `results.uids` to `uids` so group notifications work as well.
julianlam/nodebb-plugin-mentions,barisusakli/nodebb-plugin-mentions,exo-do/nodebb-plugin-mentions-exodo,drewdotpro/nodebb-plugin-mentions