Activate User Badges plugin on Rosetta forums

[SergeyBiryukov]

[4138] adds moderator badges to forum replies, and [4146] hides user role.

However, the User Badges plugin is not activated on Rosetta forums, so there's no longer a way to distinguish moderators from regular users at all.

[ocean90]

In 4149:

Support Forums, User Badges: Check if class exists before using it.

The class is part of the Support Forums plugin.

See #2085.

[ocean90]

The plugin is now activated for all support forums.