fix: allow mode as argument

[younik]

Description

After #2706, render with Wrappers doesn't work anymore with mode as argument without keyword.
For instance, the following will throw an error:

env = gym.make("FrozenLake-v1")
env.reset()
env.render('rgb_array')

This should fix this.

Type of change

• 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]

LGTM