Fix Covers position and target level

[slajob]

Hi, I make some fixes to make it working. I tested it on my KADRILJ roller blind

1. Covers level Current_cover_position is a integer so it's not callable.

   File "/workspaces/core/custom_components/dirigera_platform/cover.py", line 95, in current_cover_position
     return self._json_data.attributes.blinds_current_level()
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   TypeError: 'int' object is not callable

2. Covers control attribute Changed _set_targetposition attribute to _set_targetlevel.

   File "/workspaces/core/custom_components/dirigera_platform/cover.py", line 136, in set_cover_position
   print(self._json_data.set_target_position(position))
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   AttributeError: 'Blind' object has no attribute 'set_target_position'

[sanjoyg]

Thank you @slajob, merged!