Raise error for pusher-v4 environment when mujoco>=3

[Kallinteris-Andreas]

Description

#950 noticed that pusher-v4 had collision issues which was isolated to a bug fixed in mujoco==3.0.0
This collision issue has a major implement on performance, therefore, raising an error for pusher-v4 when mujoco>=3
The issue will be fixed in pusher-v5

[Kallinteris-Andreas]

What do we do for testing?

[pseudo-rnd-thoughts]

What do we do for testing?

Remove from the set of testing environments

We could add a specialist CI case where mujoco < 3 is installed just in case.
But with v5 fixing the issue, I don't imagine many people will use it.

Is there anyway that we can check that a similar bug doesn't exist in other environments?

[Kallinteris-Andreas]

1. To test that no other environment was broken With Mujoco 3.0 . It should be sufficient to train a single episode. Render the trained policy. And ensure that everything looks fine

[pseudo-rnd-thoughts]

@Kallinteris-Andreas Were you planning on anymore changes?

[Kallinteris-Andreas]

I have no idea why this is passing CI, pusher v4 should be failing its instanciacion

[pseudo-rnd-thoughts]

It does but try_make_env catches the error and prevents the environment from being run

[Kallinteris-Andreas]

Did not realize you commited to it, makes sense now