text: Title: [Bug Report] `MuJoCo/Walker2d` left foot has different friction than right foot
  Body: ### Describe the bug
  
  Right foot has a friction coeff of 0.9
  https://github.com/Farama-Foundation/Gymnasium/blob/main/gymnasium/envs/mujoco/assets/walker2d.xml#L25
  left foot has a friction coeff of 1.9
  https://github.com/Farama-Foundation/Gymnasium/blob/main/gymnasium/envs/mujoco/assets/walker2d.xml#L38
  
  This issue was previously reported, but not addressed.
  https://github.com/openai/gym/issues/1068
  https://github.com/openai/gym/issues/1646
  
  from what I can tell, this is most likely a typo
  both were supposed to be 1.9 (or 2.0)
  
  Since `Walker2d` and `Hopper` will be getting new models in v5 (cause https://github.com/deepmind/mujoco/issues/833)
  should this be fixed there? 
  
  ### Code example
  
  _No response_
  
  ### System info
  
  _No response_
  
  ### Additional context
  
  _No response_
  
  ### Checklist
  
  - [X] I have checked that there is no similar [issue](https://github.com/Farama-Foundation/Gymnasium/issues) in the repo
  