Modify the method name from `get_state` to `get_joint_state`

[akhilsathuluri]

The method get_state currently returns only the joint state and should be named so, to prevent confusion.

https://github.com/ami-iit/comodo/blob/8cbd5f5bc6f65a1385a646188abf999844244d30/src/comodo/mujocoSimulator/mujocoSimulator.py#L124-L130