Add more helpful error messages if users use a mixture of Gym and Gymnasium

[pseudo-rnd-thoughts]

Description

I have found several users using a mixture of Gym and gymnasium, I believe due to thinking that

import gymnasium as gym 
from gym.utils import play

will causes the second statement to use gymnasium not gym mistakenly.

This PR adds more helpful error checking for check_env, make and the passive environment checker that runs in the background on make.
Tests are included but will be turned off by default as the CI doesn't install gym so pytest.importorskip is used if users include gym locally