Run interpolation before Update

[janhohenheim]

This way, systems running in Update already operate on the final Transform and we don't need to check for changes in Update. Per discussions on Discord we recently had in #ecs-dev, this schedule was determined to be the one most useful for interpolation.
See also this companion PR in Bevy: bevyengine/bevy#14881

[janhohenheim]

Note: this PR will make interpolated objects ignore changes to transform that happen in RustFixedMainLoop, foo.before(run_fixed_main) :/
In effect, this means you need to make sure your camera is not interpolated. Which you of course want anyways, but it shouldn't be necessary to annotate that explicitly, as it won't be moved in fixed updates anyways.

[Jondolf]

This breaks user changes done in e.g. Update. In those schedules, changing the translation should be equivalent to teleporting the object, which requires resetting the easing states.

An easy way to see how this breaks it is by testing the chain_2d example in Avian. The chain is moved (via mouse) in Update, but with this PR, the interpolation breaks the movement because the easing states aren't reset appropriately (I think), and as a result, the physics positions are never updated.

[janhohenheim]

Huh, I see. Unfortunately, I don't quite understand the internal workflow of the interpolation, so I'll close the PR and create an issue instead.