Reverts #100533.
Fixes #100515.
Fixes #100700.

This pull request does two things:

1. It reverts the changes to jolt_contact_listener_3d.cpp introduced in #100533, due to taking a different approach to solving #100515.
2. It solves #100515 by instead emulating what Godot Physics does, which is to only clear the list of contacts while a body is actually active/awake. This means we're now deliberately keeping (potentially stale) contacts around when a body goes to sleep, in order to better facilitate contact-based logic in scripts, as discussed in #100533.