[Cleanup] Remove GetMaxRank() from aa_ability.cpp/aa_ability.h (#3347)

# Notes
- This is unused.

zone/aa_ability.cpp

@@ -21,22 +21,10 @@
 #include "masterentity.h"
 #include "aa_ability.h"
 
-AA::Rank *AA::Ability::GetMaxRank() {
-	if(!first)
-		return nullptr;
-	
-	Rank *current = first;	
-	while(current->next) {
-		current = current->next;
-	}
-
-	return current;
-}
-
 AA::Rank *AA::Ability::GetRankByPointsSpent(int current_level) {
 	if(current_level == 0)
 		return nullptr;
-	
+
 	if(!first)
 		return nullptr;
 
@@ -65,6 +53,6 @@ int AA::Ability::GetMaxLevel(Mob *who) {
 		max_level++;
 		current = current->next;
 	}
-	
+
 	return max_level;
-}
+}

zone/aa_ability.h

@@ -37,7 +37,6 @@ public:
 	Ability() { }
 	~Ability() { }
 
-	Rank *GetMaxRank();
 	Rank *GetRankByPointsSpent(int current_level);
 	int GetMaxLevel(Mob *who);