Core/Quests: Remove CastedCreatureOrGO method

- Remove EAI's ACTION_T_CAST_EVENT and ACTION_T_CAST_EVENT_ALL
- Remove SAI's SMART_ACTION_CALL_CASTEDCREATUREORGO
- Split QUEST_TRINITY_FLAGS_KILL_OR_CAST into QUEST_TRINITY_FLAGS_KILL and QUEST_TRINITY_FLAGS_CAST
- Assign QUEST_TRINITY_FLAGS_CAST to all the quests that were using RequiredSpellCastX
- (unrelated) Fix a warning in Player.cpp
- Replace CastedCreatureOrGO usage in scripts by KilledMonsterCredit

TODO: Convert the two EAI scripts commented out in the .sql to proper SAI

Closes #10667