[3.x] Physics Interpolation - fix client interpolation pump

[lawnjelly]

Client interpolation pump is moved AFTER the physics tick, after physics objects have been moved. This is necessary because the current transform is also updated during the pump.

Fixes #102142

Notes

• This was an oversight for client interpolation that seemed to only cause problems for physics objects, and only in the case where more than one physics tick took place before the frame.
• The server side pumps don't can take place before the tick because setting transforms will update the current as they come in, however for the client side interpolation, we have to wait until all changes have been made before setting the current transform.
• This is one of those bugs that is super obvious in retrospect 😁 . It may also fix some other behaviour on the first frame of get_global_transform_interpolated().
• I've tested using non-physics and physics objects, and the first frames of following and all looks good, even in the issue conditions (faster tick rate than frame rate).
• Should be forward ported to 4.x @rburing .