DRC flags aperture bridging error for mask aperture over graphical copper item (rectangle, circle, non-assigned zone)

Description

Placing a soldermask-layer element over an graphical item (rectangle/circle) and running the drc: this will be flagged as drc-error: solder mask aperture bridges items with different nets.

I think the reason is that the graphical copper items don't have net at all.

Affects also zones which have no net assigned.

Reminds me on issue #10189 (closed).

Steps to reproduce

1. open attached project, open board
2. run drc
3. get drc-error: solder mask aperture bridges items with different nets

drc_mask_bridges.zip

KiCad Version

Application: KiCad PCB Editor (64-bit)

Version: (6.99.0-1004-gf0e4448a9d), release build

Libraries:
	wxWidgets 3.1.5
	FreeType 2.11.1

Platform: Windows 10 (build 19043), 64-bit edition, 64 bit, Little endian, wxMSW

	wxWidgets: 3.1.5 (wchar_t,wx containers)
	Boost: 1.76.0
	OCC: 7.6.0
	Curl: 7.78.0-DEV
	ngspice: 36
	Compiler: Visual C++ 1928 without C++ ABI

Build settings:
	KICAD_USE_OCC=ON
	KICAD_SPICE=ON