Fix is_health_initialized variable not being set to true

reframework/autorun/MHR_Overlay/Monsters/large_monster.lua

@@ -620,6 +620,8 @@ function this.update_health(enemy, monster)
 		monster.capture_percentage = capture_health / max_health;
 	end
 
+	monster.is_health_initialized = true;
+
 	return physical_param;
 end
 

reframework/autorun/MHR_Overlay/Monsters/small_monster.lua

@@ -237,6 +237,8 @@ function this.update_health(enemy, monster)
 	if max_health ~= 0 then
 		monster.health_percentage = health / max_health;
 	end
+
+	monster.is_health_initialized = true;
 end
 
 function this.draw(monster, cached_config, position_on_screen, opacity_scale)