Added zoom deactivation

[PlayfulMathematician]

Overview: What does this pull request change?

This adds the ability to deactivate zooming as described in #3009

Motivation and Explanation: Why and how do your changes improve the library?

This adds the ability to deactivate zooming, it is very asymmetric how we the library has the ability to activate zooming but not deactivate it.

Links to added or changed documentation pages

Further Information and Comments

This is based on my old PR over here: #3009

Reviewer Checklist

• The PR title is descriptive enough for the changelog, and the PR is labeled correctly
• If applicable: newly added non-private functions and classes have a docstring including a short summary and a PARAMETERS section
• If applicable: newly added functions and classes are tested

[nikolajmunk]

I've never used a ZoomedScene in my life so take this with whatever size grain of salt it needs: would it not make sense to mirror the existing activate_zooming method more closely? I.e., playing an animation if animate is True and setting zoom_activated to False (though AFAICT this currently does literally nothing).