PCB Editor Appearance Manager: user defined layers always named in default language

Description

Although the language is set to English (or any other language) via the preferences menu, in the Appearance Manager the user defined layers 1 to 9 stay always named in the Default language (obviously the system language of the operating system behind) which in my case is German.

Steps to reproduce

1. In the preferences menu set the language to any language other than the default language
2. See in the PCB Editor's Appearance Manager that the user defined layers user.1 to user.9 remain their names from the default language

KiCad Version

Application: KiCad PCB Editor

Version: (6.0.5), release build

Libraries:
	wxWidgets 3.0.5
	libcurl/7.83.1 OpenSSL/1.1.1o zlib/1.2.12 brotli/1.0.9 zstd/1.5.2 libidn2/2.3.2 libpsl/0.21.1 (+libidn2/2.3.0) libssh2/1.10.0 nghttp2/1.47.0

Platform: Linux 5.15.41-1-MANJARO x86_64, 64 bit, Little endian, wxGTK, KDE, x11

Build Info:
	Date: May  3 2022 02:43:29
	wxWidgets: 3.0.5 (wchar_t,wx containers,compatible with 2.8) GTK+ 3.24
	Boost: 1.78.0
	OCC: 7.5.3
	Curl: 7.83.0
	ngspice: 36
	Compiler: GCC 11.2.0 with C++ ABI 1016

Build settings:
	KICAD_USE_OCC=ON
	KICAD_SPICE=ON