[Footprint editor] 3d model editor rotation increment/decrement buttons don't work

Description

If a 3D model is currently at a non-cardinal angle, the increment/decrement controls don't work right. They are intended to add or subtract 90° from model rotation, but they do this instead:

In fact, even manually entering angles greater than 180° or less than -180° causes it to "correct" those angles to entirely wrong numbers; 198° for instance gets "corrected" to 18° (rather than the correct equivalent of -162°).

Steps to reproduce

1. Add a 3D model to a footprint. Manually set any of its rotation angles to anything that is not a multiple of 90°.
2. Click the up and down arrow controls on that angle repeatedly.

KiCad Version

Application: KiCad Footprint Editor x64 on x64

Version: 10.0.1, release build

Libraries:
	wxWidgets 3.3.2 
	FreeType 2.13.3
	HarfBuzz 12.3.0
	FontConfig 2.17.1

Platform: Windows 10 (build 19045), 64-bit edition, 64 bit, Little endian, wxMSW
OpenGL: Intel, Intel(R) UHD Graphics, 4.6.0 - Build 31.0.101.2130

	wxWidgets: 3.3.2 (wchar_t,STL containers)
	Boost: 1.90.0
	OCC: 7.9.2
	Curl: 8.18.0
	ngspice: 46
	Compiler: Visual C++ 1944 without C++ ABI
	KICAD_IPC_API=ON
	KICAD_USE_PCH=OFF

Locale: 
	Lang: en_US
	Enc: UTF-8
	Num: 1,234.5
	Encoded кΩ丈: D0BACEA9E4B888 (sys), D0BACEA9E4B888 (utf8)