If an animation starts on frame 1 or more, rather than frame 0, AnimationController doesn't animate it properly

[tylerhasman]

Issue details

Some animations when exported from programs such as blender can start on a frame other than 0.
This causes the animation controller to incorrectly animate the object between frames 0 to N, where N is the first actual frame of the animation.

Reproduction steps/code

Have any model with an animation that starts on a frame greater than 0.
Update the models animation controller with delta=0 such that it is on frame 0.
Observe that the model won't be on the actual first frame of the animation but instead in the default position of the model.

Version of libGDX and/or relevant dependencies

1.12.1

Please select the affected platforms

Found on Windows but is likely broken on all other platforms as well.