Some vmap and HPO related features and bug fixes

[sses7757]

Description

1. Fix a bug in BraxProblem that causes vmapped BraxProblem produces wrong graph in compilation.
2. Add num_repeats support in HPO to effectively use vmap to repeat the evaluation process for each instance.
3. Add max_vmap_level support in register_vmap_op to automatically register more levels of vmapped operator.
4. Set the maximum vmap support level of non_dominate_rank to 2 to support the num_repeats in HPO.
5. Add test cases for HPO num_repeats and Brax with HPO.

To Discuss

• Please check whether a final_step method should be added to the algorithm and workflow since some of the evolutionary algorithms have special treatment at their last steps.

Checklist

• I have formatted my Python code with ruff.
• I have good commit messages.
• If adding new algorithms, problems, operators:
  • Added related test cases.
  • Added docstring to explain important parameters.
  • Added entries in the docs.