Propagate width/height styles as width/height attributes when setting layout

[westonruter]

Summary

Addresses issue raised in support topic.

The AMP_Base_Sanitizer::set_layout() method was extracting width/height styles, but it was only considering the 100% value case. This ensures that other values are also propagated to the resulting width/height attributes on the AMP element.

Given this markup:

<iframe style="width: 100%; height: 200px;" frameborder="no" scrolling="no" src="https://player.captivate.fm/episode/495621d8-6f05-4d95-bbaa-369a9a6189e1"></iframe>

Before:

<amp-iframe
		style="width: 100%; height: 200px;"
		frameborder="0"
		scrolling="no"
		src="https://player.captivate.fm/episode/495621d8-6f05-4d95-bbaa-369a9a6189e1" 
		height="400"
		layout="fixed-height" 
		width="auto"
		sandbox="allow-downloads allow-forms allow-modals allow-orientation-lock allow-pointer-lock allow-popups allow-popups-to-escape-sandbox allow-presentation allow-same-origin allow-scripts allow-top-navigation-by-user-activation">
</amp-iframe>

After:

<amp-iframe 
		style="width: 100%; height: 200px;"
		frameborder="0"
		scrolling="no" 
		src="https://player.captivate.fm/episode/495621d8-6f05-4d95-bbaa-369a9a6189e1" 
		height="200"
		width="auto" 
		layout="fixed-height" 
		sandbox="allow-downloads allow-forms allow-modals allow-orientation-lock allow-pointer-lock allow-popups allow-popups-to-escape-sandbox allow-presentation allow-same-origin allow-scripts allow-top-navigation-by-user-activation">
</amp-iframe>

Checklist

• My code is tested and passes existing tests.
• My code follows the Engineering Guidelines (updates are often made to the guidelines, check it out periodically).

[github-actions]

Plugin builds for 7f04164 are ready 🛎️!

• Download development build
• Download production build

[westonruter]

Rebasing against develop.

[dhaval-parekh]

Change look good to me 👍

[bartoszgadomski]

QA passed

I tested this with three iframes:

Original styles	Attributes	Screenshot
width:100% height:200px	width="auto" height="200
width:25vh height:50vh	width="25vh" height="50vh"
width:123pt height:50pt	width="auto" height="400"