gerbview : high CPU usage after "Clear current layer"

Description

gerbview appears frozen, pegs the CPU at 100% for a few minutes, and keeps a high CPU usage after using "Clear current layer" to remove a complex layer.

Steps to reproduce

1. extract and open attached fab layer : hmc862eval_FABRICATION.zip
2. in the Layers manager, right-click that layer and click "Clear current layer".
3. GUI becomes non responsive for a long period, with high CPU usage.

KiCad Version

Application: KiCad Gerber Viewer x86_64 on x86_64

Version: 7.0.10, release build

Libraries:
	wxWidgets 3.2.4
	FreeType 2.13.2
	HarfBuzz 8.3.0
	FontConfig 2.15.0
	libcurl/8.5.0 OpenSSL/3.2.0 zlib/1.3 brotli/1.1.0 zstd/1.5.5 libidn2/2.3.4 libpsl/0.21.2 (+libidn2/2.3.4) libssh2/1.11.0 nghttp2/1.58.0

Platform: Manjaro Linux, 64 bit, Little endian, wxGTK, lxqt, x11

Build Info:
	Date: Dec 30 2023 03:23:58
	wxWidgets: 3.2.4 (wchar_t,wx containers) GTK+ 3.24
	Boost: 1.83.0
	OCC: 7.7.2
	Curl: 8.5.0
	ngspice: 41
	Compiler: GCC 13.2.1 with C++ ABI 1018

Build settings:
	KICAD_USE_EGL=ON
	KICAD_SPICE=ON