Converts some actions to mob cooldown actions (#77680)

## About The Pull Request

It has come to my attention that it isn't possible for admins to grant
the abilities to place web, lay eggs, and issue commands to spiders to
arbitrary mobs. This refactors Spider, Goliath, and Meteor Heart
abilities (hey what do you know I last touched all of those) such that
they can.

## Why It's Good For The Game

You **can** create the spider pig as an event.

## Changelog

🆑
admin: Adds Spider, Goliath, and Meteor Heart actions to the "Grant Mob
Action" menu.
/🆑

code/modules/mob/living/basic/lavaland/watcher/watcher_gaze.dm

@@ -11,7 +11,7 @@
 	cooldown_time = 30 SECONDS
 	check_flags = AB_CHECK_CONSCIOUS | AB_CHECK_INCAPACITATED
 	click_to_activate = FALSE
-	shared_cooldown = null
+	shared_cooldown = NONE
 	/// At what range do we check for vision?
 	var/effect_radius = 7
 	/// How long does it take to play our various animation stages

code/modules/mob/living/basic/lavaland/watcher/watcher_overwatch.dm

@@ -11,7 +11,7 @@
 	cooldown_time = 20 SECONDS
 	check_flags = AB_CHECK_CONSCIOUS | AB_CHECK_INCAPACITATED
 	click_to_activate = TRUE
-	shared_cooldown = null
+	shared_cooldown = NONE
 	/// Furthest range we can activate ability at
 	var/max_range = 7
 	/// Type of projectile to fire