fix(envs): Enable auto reset for MuJoCo envs

[dtch1997]

Description

Enable AutoReset wrapper for Mujoco envs.

Motivation and Context

Why is this change required? What problem does it solve?
If it fixes an open issue, please link to the issue here.
You can use the syntax close #15213 if this solves the issue #15213

• I have raised an issue to propose this change (required for new features and bug fixes)

Closes #268

Types of changes

What types of changes does your code introduce? Put an x in all the boxes that apply:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds core functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (update in the documentation)

Checklist

Go over all the following points, and put an x in all the boxes that apply.
If you are unsure about any of these, don't hesitate to ask. We are here to help!

• I have read the CONTRIBUTION guide. (required)
• My change requires a change to the documentation.
• I have updated the tests accordingly. (required for a bug fix or a new feature)
• I have updated the documentation accordingly.
• I have reformatted the code using make format. (required)
• I have checked the code using make lint. (required)
• I have ensured make test pass. (required)

[codecov]

Codecov Report

Merging #269 (772d0fd) into main (80c2c23) will not change coverage.
The diff coverage is 100.00%.

❗ Current head 772d0fd differs from pull request most recent head 7432fc2. Consider uploading reports for the commit 7432fc2 to get more accurate results

@@           Coverage Diff           @@
##             main     #269   +/-   ##
=======================================
  Coverage   97.01%   97.01%           
=======================================
  Files         138      138           
  Lines        6991     6991           
=======================================
  Hits         6782     6782           
  Misses        209      209           

Files Changed	Coverage Δ
omnisafe/envs/mujoco_env.py	93.33% <100.00%> (ø)

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[Gaiejj]

LGTM.