Fix `move_and_slide` wall slide acceleration (3D)

[rburing]

When travel is high enough, keep the global position resulting from the move_and_collide call, and set the motion to the remainder from the move_and_collide call. This ensures travel is taken into account once, rather than twice.

This is also consistent with the other branch:

https://github.com/godotengine/godot/blob/2efbc6bfb3b4f49a6bc75b3d367cfe81eeddbf3a/scene/3d/physics/character_body_3d.cpp#L241-L242

Thanks to @Calinou for extra testing.

• Fixes https://github.com/godotengine/godot/issues/66249
• Fixes https://github.com/godotengine/godot/issues/74553
• Fixes https://github.com/godotengine/godot/issues/90410

[rburing]

For ease of reviewing: the travel is taken into account in the call

https://github.com/godotengine/godot/blob/2efbc6bfb3b4f49a6bc75b3d367cfe81eeddbf3a/scene/3d/physics/character_body_3d.cpp#L159

which passes p_test_only = false into move_and_collide:

https://github.com/godotengine/godot/blob/80c600d86b6fed05fdb35d5dd95267a8a95fe74d/scene/3d/physics/physics_body_3d.cpp#L155-L159

[akien-mga]

Thanks!

[akien-mga]

Cherry-picked for 4.2.3.