[Bots] Add attack flag when told to attack (#4490)

This adds a flag to mobs that are told to attack by their owner to prevent unintended attacks.

Previously, if you were to send your bots to attack a target and then switch targets: before casters land their spell or if melee (especially anyone with pets)  hasn't engaged before the target switch, they could switch to your new target and attack.

This adds a flag upon attack and bots will only attack flagged targets.

zone/bot_commands/attack.cpp

@@ -35,6 +35,11 @@ void bot_command_attack(Client *c, const Seperator *sep)
 		return;
 	}
 
+	if (!c->HasBotAttackFlag(target_mob)) {
+		target_mob->SetBotAttackFlag(c->CharacterID());
+		target_mob->bot_attack_flag_timer.Start(10000);
+	}
+
 	size_t attacker_count = 0;
 	Bot *first_attacker = nullptr;
 	sbl.remove(nullptr);