Fix wrappers.vector.HumanRendering

[RogerJL]

fixed num_rows and num_cols
break loop when fewer environments that sub-images added tests

Description

Set the variables that are used, and do not index out of bounds

Fixes # (1068)

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
• 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 and adding testing.
I did some more comprehensive tests, see the updated testing file
Also, I found the old method of determining a sub-environment rendering x,y had issues so I updated that to better code