Fix spinners potentially displaying incorrect SPM numbers

[ekrctb]

Fix #21221

[frenzibyte]

It would be helpful to provide a description as to why the original check wasn't enough. But upon investigating this myself, it turns out that the bug is caused by the following scenario:

• User seeks to end and finishes seeking
• SPM calculator adds a rotation record of current time
• User presses right arrow, which causes the game to actually seek backwards because the clock already passed gameplay time and the seek got clamped to gameplay time (last object's end time).
• Elapsed frame time becomes negative, and the calculator bypasses the original elapsed != 0 check in master
• SPM calculator adds rotation record of current time, which is actually equal to last record's time

We can't solve this by changing the orgiinal check to account for negative elapsed time, because that would break rewind. Therefore the change here to check on current time rather than elapsed looks sound.

Such scenario is very dependant on time, so a test scene doesn't look to be easily feasible.