Include component ID in all physics events

[ashtonmeuser]

An alternative to the problem raised in #56. Related PRs: #56, #57, #72.

This is perhaps the cleanest solution to the problem of collision exits due to deleted identities, albeit the most breaking change.

Rather than cacheing recently-deleted identities to be surfaced in PredictedRigidbody2/3D.onCollisionExit(GameObject other, ...), this implementation includes a PredictedComponentID in all physics events making the equivalent PredictedRigidbody2/3D.onCollisionExit(GameObject other, PredictedComponentID otherId, ...). The checks in Assets/PurrDiction/Runtime/PhysicsEvents/Predicted2DPhysics.cs:124 and Assets/PurrDiction/Runtime/PhysicsEvents/Predicted3DPhysics.cs:62 now fire exit events despite the other GameObject being falsy.

In short, the issue with collision/trigger exit events is that we're not guaranteed to have a valid GameObject to refer to. Therefore, with the current physics event signatures, we can either hide the exit event (current behaviour) or present the event with a null GameObject. Neither of these options are great. This proposal includes the PredictedComponentID in all physics events which is guaranteed to exist despite the GameObject being null.

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[ashtonmeuser]

Yet another alternative would be to bundle the other PredictedComponentID with the collision information along with DisposableList<Physics2DContactPoint> evContacts. This would be similarly API breaking. Trigger events would likely stay the same as proposed by this PR or else bundled collision info with empty contacts.