fix(Core/Battleground/PvPstats): correct bracket_id for AV (#10677)

data/sql/updates/pending_db_characters/rev_1644943100668922283.sql

@@ -0,0 +1,5 @@
+INSERT INTO `version_db_characters` (`sql_rev`) VALUES ('1644943100668922283');
+
+UPDATE `pvpstats_battlegrounds`
+SET `bracket_id` = `bracket_id` + 1
+WHERE `type` = 1;

src/server/game/Battlegrounds/Battleground.cpp

@@ -2017,5 +2017,5 @@ void Battleground::RewardXPAtKill(Player* killer, Player* victim)
 
 uint8 Battleground::GetUniqueBracketId() const
 {
-    return GetMinLevel() / 10;
+    return GetMaxLevel() / 10;
 }