mrtrix3.app: Pylint fixes for 3.12 compatibility

Fixes to 6da0f39.

python/mrtrix3/app.py

@@ -583,7 +583,7 @@ class Parser(argparse.ArgumentParser):
   #   which will derive from both pathlib.Path (which itself through __new__() could be Posix or Windows)
   #   and a desired augmentation that provides additional functions
   @staticmethod
-  def make_userpath_object(base_class, *args, **kwargs):
+  def make_userpath_object(base_class, *args):
     abspath = os.path.normpath(os.path.join(WORKING_DIR, *args))
     super_class = pathlib.WindowsPath if os.name == 'nt' else pathlib.PosixPath
     new_class = type(f'{base_class.__name__.lstrip("_").rstrip("Extras")}',
@@ -593,7 +593,7 @@ def make_userpath_object(base_class, *args, **kwargs):
       instance = new_class.__new__(new_class, abspath)
     else:
       instance = new_class.__new__(new_class)
-      super(super_class, instance).__init__(abspath)
+      super(super_class, instance).__init__(abspath) # pylint: disable=bad-super-call
     return instance
 
   # Classes that extend the functionality of pathlib.Path