Scripts/Naxxramas: Faerlina cleanup:

- Move greeting to areatrigger instead of MoveInLineOfSight hack
- Clean up add spawn handling to prevent various glitching with combinations of evade state and add aggro
- Ensure all adds are always pulled alongside the boss and vice versa
- Add missing texts.
- Fix a bug in the core that prevents castable-while-dead spells (such as Widow's Embrace) from appearing on possess bars.

src/server/game/Entities/Unit/Unit.cpp

@@ -13769,7 +13769,7 @@ void CharmInfo::InitPossessCreateSpells()
         {
             uint32 spellId = _unit->ToCreature()->m_spells[i];
             SpellInfo const* spellInfo = sSpellMgr->GetSpellInfo(spellId);
-            if (spellInfo && !spellInfo->HasAttribute(SPELL_ATTR0_CASTABLE_WHILE_DEAD))
+            if (spellInfo)
             {
                 if (spellInfo->IsPassive())
                     _unit->CastSpell(_unit, spellInfo, true);
@@ -13797,7 +13797,7 @@ void CharmInfo::InitCharmCreateSpells()
         uint32 spellId = _unit->ToCreature()->m_spells[x];
         SpellInfo const* spellInfo = sSpellMgr->GetSpellInfo(spellId);
 
-        if (!spellInfo || spellInfo->HasAttribute(SPELL_ATTR0_CASTABLE_WHILE_DEAD))
+        if (!spellInfo)
         {
             _charmspells[x].SetActionAndType(spellId, ACT_DISABLED);
             continue;