DRC: silkscreen clipped by soldermask not working

Description

This was reported on the forum (https://forum.kicad.info/t/pcb-editor-drc-doesnt-see-silkscreen-on-pads/41271).

The check "silkscreen clipped by soldermask" is not working.

affects v7 and v799.

v6.0.10 was working ok.

Steps to reproduce

1. open attached project, open board: slikscreen_clipped_by_soldermask.zip
2. notice: some silkscreen-elements are deliberately positioned at the footprint pads
3. run DRC
4. notice: no warning / error for the silkscreen elements overlapping the pads (and also overlapping the extra placed mask-rectangles)

KiCad Version

Application: KiCad PCB Editor x64 on x64

Version: 7.0.1-37-g94fd0df2e2, release build

Libraries:
	wxWidgets 3.2.2
	FreeType 2.12.1
	HarfBuzz 6.0.0
	FontConfig 2.14.1

Platform: Windows 10 (build 19044), 64-bit edition, 64 bit, Little endian, wxMSW

	wxWidgets: 3.2.2 (wchar_t,wx containers)
	Boost: 1.81.0
	OCC: 7.6.3
	Curl: 7.88.1-DEV
	ngspice: 39
	Compiler: Visual C++ 1934 without C++ ABI

Build settings:
	KICAD_SPICE=ON