Fixed valgrind issues.

Signed-off-by: Deukhoofd <Deukhoofd@gmail.com>

tests/BattleTests/EventHookTests.cpp

@@ -41,5 +41,6 @@ TEST_CASE("Build and use event hook with different types", "[Battling]") {
     eventHook.Trigger<FaintEvent>(nullptr);
     eventHook.Trigger<DamageEvent>(nullptr, DamageSource::AttackDamage, 0, 0);
     eventHook.Trigger<FaintEvent>(nullptr);
+    eventHook.FinishListening();
 }
 #endif