[3.x] Improve TextureProgress.set_radial_initial_angle() by removing loops

[arkology]

Backport #98816 to 3.x
Fixes #60338

Some notes:

• There are not Math::is_finite() and Math::fposmodp() in 3.x, so Math::is_finite() replaced with isfinite() from math.h stdlib (just expanding function Math::is_finite() from 4.x branch - feel free to suggest how it could be done differently), and Math::fposmodp() replaced with Math::fposmod() (same as Math::fposmodp() but with more checks).
• No unit tests added (as they are 4.x privilege), but in editor it works as expected.

[arkology]

cc @AThousandShips please take a look when you have time.
Thanks!