gdb: Workaround optimized out quark_seq_id

On fedora 38 (and it was the case in previous releases), the quark_seq_id is optimized out so getting quarks from the global variable always failed. This patch works around that by assuming it is a valid quark whenever the quark_seq_id is not accessible.

This issue often manifested as Python Exception <class 'TypeError'>: can only concatenate str (not "NoneType") to str when debugging as other parts of the code assume that getting the quark for a GType name will work.