Added vector env support to StepAPICompatibility wrapper.

[nidhishs]

Description

This PR adds support for vector environments in StepAPICompatibility wrapper. Previously, the wrapper was incompatible due to not passing proper flag to the underlying step_api_compatibility utility function.

Fixes #237

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• I have run the pre-commit checks with pre-commit run --all-files (see CONTRIBUTING.md instructions to set it up)
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[pseudo-rnd-thoughts]

Thanks for the PR, this looks good