The use of `const` for Objective-C object pointer is not standard and
generally unsound. Unlike a C++ class, which has support for const and
non-const methods. An Objective-C object will still respond to mutable
selectors even if its object pointer is const, making it semantically
useless.
Another problem with const Objective-C object is that they cannot be
properly passed into other Objective-C object selectors due to type
differences. Even if that selector didn't modify the underlying object.
For consistency with general Objective-C code style guidelines, usage of
const pointer syntax (`Class *const`) were also removed.
Ref #126772
Pull Request: https://projects.blender.org/blender/blender/pulls/126768