Embedded throwables are unembedded when the parent entity is destroyed

[Centronias]

BUT it only applies to entities which emit a DestructionEventArgs or BeingGibbedEvent when they're destroyed.

About the PR

Tracks projectiles embedded in an object, and un-embeds them when either [] is raised on the object (presently just before they're deleted).

Why / Balance

Fixes #22823

Technical details

• Added HasProjectilesEmbeddedComponent, which is applied to objects when a projectile is embedded in them
  • this component tracks the EntityUids of the objects that're embedded
• Split the code that's used to remove embedded objects manually into one function which preserves that functionality, and a new function which reuses 99% of the implementation of that functionality to be able to arbitrarily un-embed objects at will.
  • the un-embedding function now additionally checks that the object is, in fact, embedded in something by looking for itself in its parent's HasProjectilesEmbeddedComponent.
• Added two event subscriptions to Server's ProjectileSystem which checks an entity for children with EmbeddableProjectile, and uses this shared un-embedding code to unembed them.
  • This is run when an entity with HasProjectilesEmbeddedComponent has either DestructionEventArgs or BeingGibbedEvent raised
• Tweaks to exactly how we call the embedding code such that embedding (hopefully) happens before destruction
  • Before I added this, I was running into nondeterministic behavior where different objects would survive or not when thrown at water tanks (eg. spear didn't, but plasma spear did -- quite weird)

Known Issues

In general, there're still a ton of cases where an embedded object will be destroyed when its parent id deleted. This is because there're so many cases where entities are just deleted or enqueued for deletion without raising any events to hook in some "pls drop embedded stuff before you die" logic. However, I think a great many of these are relatively violent in-game events (eg. gas canisters exploding due to overpressurization) that it won't be quite so noticeable.
The only solution I can think of for this would be to do some kind of audit of all places where things're deleted and make sure there's some generic "entity is being removed from game due to 'IC' reasons" event so that a hook can be implemented to react to it.
("IC reasons" as opposed to things like particle effects ending, admin deletion, etc.)

Because I only order embedding to occur before Destructible destruction, it's conceivable there's some case where something that'd embed in a body will gib it in the same interaction, and that'll have the same projectile-deleting effect. But, I figure that that's a markedly rarer case that's not worth adding a bunch of additional before: [ ... ] conditions for.
I will leave it to the wisdom of the reviewers.

Media

unembed-all.mp4

Old revision media

LeReusableSpear.mp4

@YotaXP 's mouse-eating case:

eatmousedropsknife.mp4

Requirements

• I have read and am following the Pull Request and Changelog Guidelines.
• I have added media to this PR or it does not require an ingame showcase.

Breaking changes

None? Possibly something coming from the system ordering?
Added public method to ProjectileSystemShared to unembed Entity<EmbeddableProjectileComponent>?

Changelog
🆑

• fix: Destroying objects with projectiles stuck to them will now leave the projectiles on the ground rather than deleting them.

[YotaXP]

Eating a mouse with an embedded item still deletes the item. (This happened in a round recently which is why I thought of it. lol)

[YotaXP]

I wouldn't say I'm familiar enough with the codebase at this time to give a proper review (my computer is too potato to even work in it), but I'll do what I can with my general C# knowledge.

[github-actions]

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