[Inspector UXR] Rotated text labels in layout explorer

_This issue has been broken out of https://github.com/flutter/devtools/issues/2890_

### Rotated text labels

We feel the vertically rotated labels are difficult to read, requiring the user to tilt their head.


### Suggestions

* Avoid having labels that require tilting your head to read them.
* Rearrange the layouts so that labels can be rearranged or repositioned to be easily readable.
* Consider the content that needs to be shown here
* Evaluate if showing “width x height” in the middle of the component would make more sense
* Evaluate clarifying the box constraints display.