Fixes some incorrect before_casts (personality commune, revenant) (#70339)

before_cast returns a bitflag, shouldn't return a bool. Bools will break it, TRUE especially cause it's the same as CANCEL_CAST. See

    Fixes tesla blast #69394

Fixes #70302

I'll see if this can be unit tested as well

code/modules/antagonists/revenant/revenant_abilities.dm

@@ -195,7 +195,7 @@
 /datum/action/cooldown/spell/aoe/revenant/before_cast(mob/living/simple_animal/revenant/cast_on)
 	. = ..()
 	if(. & SPELL_CANCEL_CAST)
-		return FALSE
+		return
 
 	if(locked)
 		if(!cast_on.unlock(unlock_amount))

code/modules/spells/spell_types/self/personality_commune.dm

@@ -36,8 +36,6 @@
 		reset_cooldown()
 		return . | SPELL_CANCEL_CAST
 
-	return TRUE
-
 // Pillaged and adapted from telepathy code
 /datum/action/cooldown/spell/personality_commune/cast(mob/living/cast_on)
 	. = ..()