Scripts/Onyxia Lair: small rework
- fix crash on boss death
- avoid abusing during phase switch
- added better facing through trigger
- corrected some timers
- corrected inhabit type
- cleanup and inheriting some BossAI functionalities instead of custom stuff
Merge pull request #13008 from mik1893/onyxia

Scripts/Onyxia Lair: small rework