plot board: settings for untented via not respected

Description

v9 introduced the independent setting for tented/untented vias. This works well in the pcb editor and in the 3D viewer. But the output to gerber disrespects this setting and takes all vias as tented, so all openings/via mask removal is lost in the gerber files.

Affects also other output formats like pdf and svg.

Checked with the old board plot dialog, not with the new jobset feature.

Setting high priority as this will affect the manufactured boards.

Steps to reproduce

1. open attached project, open board: tented_vias.zip
2. notice 6 columns of via. Each column has a different setting for front/back via tenting. This covers all 6 combination possible in the via parameter dialog. Only the option "take from design rules" is unused. (Don't know how that works).
3. enable F.Mask layer, set display mode to "Hide": shows 3 columns with openings in F-Mask (Picture 2)
4. enable B.Mask layer, set display mode to "Hide": shows 3 columns with openings in B-Mask (Picture 3)
5. File-->Fabrication output-->gerber, to create the gerber files (prefabricated in subfolder "production") (picture4)
6. load mask layer into gerber viewer: no mask openings in front/back mask layer.

KiCad Version

Application: KiCad PCB Editor x64 on x64

Version: 9.0.0-rc1-273-g6c43c25b4c, release build

Libraries:
	wxWidgets 3.2.6
	FreeType 2.13.3
	HarfBuzz 10.0.1
	FontConfig 2.15.0

Platform: Windows 10 (build 19045), 64-bit edition, 64 bit, Little endian, wxMSW
OpenGL: Intel, Intel(R) HD Graphics 4000, 4.0.0 - Build 10.18.10.5161

	wxWidgets: 3.2.6 (wchar_t,wx containers)
	Boost: 1.86.0
	OCC: 7.8.1
	Curl: 8.10.1-DEV
	ngspice: 43
	Compiler: Visual C++ 1942 without C++ ABI
	KICAD_IPC_API=ON

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