Symbol shape custom fill color inconsistency

Description

Symbol shape with custom fill color, when placed within a rectangle with "Fill with body background color" selected, will not render the custom color. (Rectangle's fill has bigger priority than other shapes with custom color). This behavior is different when using circles. (Custom color is still visible). See screenshots below.

Steps to reproduce

1. Open symbol editor and edit/create any symbol.
2. Create a shape (polyline or circle and assign a custom fill color to it.
3. Create a rectangle overlapping previously created custom shape.
4. Select "Fill with body background color" in the rectangle's properties.

KiCad Version

Application: KiCad Symbol Editor (64-bit)

Version: (6.99.0-3300-g087550ebd3), release build

Libraries:
	wxWidgets 3.1.7
	FreeType 2.11.1
	HarfBuzz 4.2.0
	FontConfig 2.14.0
	libcurl/7.83.1-DEV Schannel zlib/1.2.12

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

Build Info:
	Date: Sep  9 2022 07:24:53
	wxWidgets: 3.1.7 (wchar_t,wx containers)
	Boost: 1.79.0
	OCC: 7.6.0
	Curl: 7.83.1-DEV
	ngspice: 37
	Compiler: Visual C++ 1929 without C++ ABI

Build settings:
	KICAD_SPICE=ON