Make long landscape images withing quiz questions fit the available width of the container.

### Reproduction Steps

1. Create a quiz and publish that quiz.
2. Add a **Multiple** **Choice** question.
3. Set an **image** for that question, as you can see in [this screenshot](https://share.zight.com/kpueYm7R). Use a very very **long** **landscape** **image**.

### Expected Behavior
The image should fit the available width.

### Actual Behavior
The image [does not fit](https://share.zight.com/P8uwRY5B) the available width.

This issue has be recreated:
+ [x] Locally
+ [ ] On a staging site
+ [x] On a production website
+ [x] With only LifterLMS and a default theme