The Move tool does not snap to the center of a non-copper shape

Description

Steps to reproduce

1. As shown in the figure, moving the pad to the center of the F.Silkscreen layer does not automatically adsorb. Convert it to F.Cu layer and you're ready to adsorb.

KiCad Version

Application: KiCad x64 on x64

Version: 8.0.0-rc1-79-gf80094e7c5, release build

Libraries:
	wxWidgets 3.2.4
	FreeType 2.12.1
	HarfBuzz 8.3.0
	FontConfig 2.14.2

Platform: Windows 10 (构建 19045)，64位版, 64 bit, Little endian, wxMSW

	wxWidgets: 3.2.4 (wchar_t,wx containers)
	Boost: 1.83.0
	OCC: 7.7.1
	Curl: 8.5.0-DEV
	ngspice: 42
	Compiler: Visual C++ 1936 without C++ ABI

Build settings: