Don't grant Cheers for Self-Solving

[ganncamp (G Ann Campbell)]

@ganncamp

encourage marking another user’s post as the solution

Explicitly, IMO this should yield 0 cheers:

[Falco]

Thanks for the report, this is now fixed. You will need to ask for a backfill if you want to remove those points retroactively.

https://github.com/discourse/discourse-gamification/pull/101