Revert "Inject Url Generator and Translator Interface into notification mailer (#2169)"
Revert "Inject Url Generator and Translator Interface into notification mailer (#2169)"

This was actually already present and functional, so adding additional code for it
is unnecessary.

This reverts commit e627616750c35e1ed70bcd7fa35d3ab147efe866.

flarum/core,flarum/core,flarum/core