* Only fetch RSS of users who can create articles
This commit leverages changes from forem/forem#16732 and
forem/forem#16763 to ensure that we're only fetching RSS feeds for
folks who have permission to create articles.
In addition, I chose to rename the variable `user_scope` to
`users_scope` to bring consistency in the variable names.
I also chose to refactor a private method so that it wasn't setting two
instance variables but was instead returning a value that could be used
to set an instance variable.
Closesforem/forem#16487
* Amending method name
1b337b85d9