Changes to Project related settings, like netclasses, inside PCBnew, the kicad_pro is only updated after PCBnew quit

Description

When I changed the settings and save, the kicad_pro files should updated

Steps to reproduce

1. Open a project
2. Open PCBnew
3. add a new netclass in PCBnew
4. check the kicad_pro (in git managed repo ), it is not changed
5. close PCBnew
6. check again kicad_pro, it is changed

KiCad Version

Application: KiCad x86_64 on x86_64

Version: 7.0.6-14-g83dd2309e5-qdiotpi, release build

Libraries:
	wxWidgets 3.2.2
	FreeType 2.10.4
	HarfBuzz 2.7.4
	FontConfig 2.13.1
	libcurl/7.74.0 OpenSSL/1.1.1n zlib/1.2.11 brotli/1.0.9 libidn2/2.3.0 libpsl/0.21.0 (+libidn2/2.3.0) libssh2/1.9.0 nghttp2/1.43.0 librtmp/2.3

Platform: Debian GNU/Linux 11 (bullseye), 64 bit, Little endian, wxGTK, i3-gnome, x11

Build Info:
	Date: Jul  8 2023 19:21:23
	wxWidgets: 3.2.2 (wchar_t,wx containers) GTK+ 3.24
	Boost: 1.74.0
	OCC: 7.5.1
	Curl: 7.74.0
	ngspice: 34
	Compiler: GCC 10.2.1 with C++ ABI 1014

Build settings:
	KICAD_USE_EGL=ON
	KICAD_SPICE=ON