[eeschema] improve messaging of "update symbol" dialog

Description

Currently, with the update symbols from library dialog, you can uncheck everything and certain aspects of symbols will still update. This makes sense in a way (why would you bother updating symbols if you don't want anything to change), but there's nothing in the UI telling you what will still update. Implicitly updated isn't just the symbol graphics itself, but also footprint filters, and who knows what else.

Having additional checkboxes that cannot be unchecked for the always-updated things would be a quick fix. Making them un-checkable would be an added bonus, I guess if you wanted to update fields but not the symbol or something.

Steps to reproduce

KiCad Version

Application: KiCad x86_64 on x86_64

Version: 8.0.2-rc2-2-ga5ca0f4c5e, release build

Libraries:
	wxWidgets 3.2.4
	FreeType 2.11.1
	HarfBuzz 2.7.4
	FontConfig 2.13.1
	libcurl/7.81.0 OpenSSL/3.0.2 zlib/1.2.11 brotli/1.0.9 zstd/1.4.8 libidn2/2.3.2 libpsl/0.21.0 (+libidn2/2.3.2) libssh/0.9.6/openssl/zlib nghttp2/1.43.0 librtmp/2.3 OpenLDAP/2.5.17

Platform: Ubuntu 22.04.4 LTS, 64 bit, Little endian, wxGTK, X11, xubuntu, x11

Build Info:
	Date: Apr 22 2024 15:07:02
	wxWidgets: 3.2.4 (wchar_t,wx containers) GTK+ 3.24
	Boost: 1.74.0
	OCC: 7.6.3
	Curl: 7.81.0
	ngspice: 36
	Compiler: GCC 11.4.0 with C++ ABI 1016

Build settings: