Looped animations can't transition automatically in state machine

[SaracenOne]

Godot version

5f1e56f

System information

Windows 11

Issue description

The state machines AnimationNodeAnimations appears to have broken in several ways. Firstly, the AtEnd transition no longer works for animations marked as looping or ping-pong, and the progress bar for the animation always appears as 'complete' regardless of its state. The regression seems to have crept in as part of this overhaul to the animation system (991e6e9).

The font colouring also appears to be broken in the master build, but this appears to be a seperate and much more recent issue.

Steps to reproduce

Create an AnimationTree with a state machine, creation an AnimationPlayer with one or more looped animations, add one of these to the AnimationTree state machine and create an AtEnd transition to another node. The animation will never execute the transtion.

Minimal reproduction project

animation_test_1.zip

[SaracenOne]

#79400
Workaround by @TokageItLab, need to review

[TokageItLab]

As mentioned in #79400 (comment), this is not a bug exactly, but rather an expected behavior to avoid unsemantic transitions. To solve this completely, the user should be able to arbitrarily define the remaining time of the upstream AnimationNode such as I commented in #57959 (comment), but the proposal is needed first.