CADSTAR: Don't throw exceptions unknown nodes are found
Description
Follow-up from #13526
At the moment the cadstar parser throws exceptions as soon as it encounters an s-expression it does not expect. We should just log a warning instead.
KiCad Version
Application: KiCad Schematic Editor x86_64 on x86_64
Version: 7.99.0-600-g604a7d69db-dirty, debug build
Libraries:
wxWidgets 3.2.1
FreeType 2.12.1
HarfBuzz 2.7.4
FontConfig 2.13.1
libcurl/7.85.0 OpenSSL/3.0.5 zlib/1.2.11 brotli/1.0.9 zstd/1.5.2 libidn2/2.3.3 libpsl/0.21.0 (+libidn2/2.3.2) libssh/0.9.6/openssl/zlib nghttp2/1.49.0 librtmp/2.3
Platform: Ubuntu 22.10, 64 bit, Little endian, wxGTK, ubuntu, wayland
Build Info:
Date: Mar 26 2023 15:45:22
wxWidgets: 3.2.1 (wchar_t,wx containers) GTK+ 3.24
Boost: 1.74.0
OCC: 7.6.3
Curl: 7.85.0
ngspice: 37
Compiler: GCC 12.2.0 with C++ ABI 1017
Build settings:
KICAD_STDLIB_DEBUG=OFF
KICAD_STDLIB_LIGHT_DEBUG=OFF
KICAD_SANITIZE_ADDRESS=OFF
KICAD_SANITIZE_THREADS=OFF