Fix editor not applying offsets

[peppy]

Finally. Notably, this cleans up a lot of weird logic surrounding track access / loaded state. Apart from that, I've tried to make as few changes as possible. As with other clock changes, disclaimer that this is likely not the final picture, but is made to be flexible to future changes.

• Depends on Introduce FramedBeatmapClock (and use in gameplay flow) #19828.

[smoogipoo]

Seems ok

[peppy]

I was hoping this wouldn't happen, but platform offset causes issues here.

This was actually the fix I reverted framework side (due to the performance regression).

I'll try and find an alternative solution.

[peppy]

I've fixed the failing test.

Please turn a blind eye to the fact that this change is only applied in one usage of CurrentTime in the test scene. I've tested in the editor and things behave as per expectation, but I'll revisit this weirdness when I get to doing a second pass on clocks.