[LLDB][SBSaveCore] Fix bug where default values are not propagated. (#101770)

In #100443, Mach-o and Minidump now only call process API's that take a
`SaveCoreOption` as the container for the style and information if a
thread should be included in the core or not. This introduced a bug
where in subsequent method calls we were not honoring the defaults of
both implementations.

~~To solve this I have made a copy of each SaveCoreOptions that is
mutable by the respective plugin. Originally I wanted to leave the
SaveCoreOptions as non const so these default value mutations could be
shown back to the user. Changing that behavior is outside of the scope
of this bugfix, but is context for why we are making a copy.~~

Removed const on the savecoreoptions so defaults can be inspected by the
user

CC: @Michael137

lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp

@@ -355,7 +355,7 @@ size_t ObjectFilePECOFF::GetModuleSpecifications(
 }
 
 bool ObjectFilePECOFF::SaveCore(const lldb::ProcessSP &process_sp,
-                                const lldb_private::SaveCoreOptions &options,
+                                lldb_private::SaveCoreOptions &options,
                                 lldb_private::Status &error) {
   // Outfile and process_sp are validated by PluginManager::SaveCore
   assert(options.GetOutputFile().has_value());