Triggers: prevent event names from conflicting with added methods
Refs rP25373 / D3913 which removed the 'actions' suffix. The reason for this suffix was probably avoiding this type of conflict, but this new solution does a better job.
Fixes (at least) Survival of the Fittest, which used an OnOnwershipChanged trigger.
Differential Revision: https://code.wildfiregames.com/D3979