Non-breaking spaces in <foreignObject> get trimmed

[timdp]

Describe the bug
When parsing HTML in <foreignObject>, non-breaking spaces (  aka   aka  ) are getting removed.

To Reproduce

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 400 300">
  <foreignObject width="400" height="300">
    <div xmlns="http://www.w3.org/1999/xhtml" style="width: 100%; height: 100%; background: blue; color: white; display: flex; justify-content: center; align-items: center;">
      <div>foo </div>
      <div>bar&#xA0;</div>
      <div>baz</div>
    </div>
  </foreignObject>
</svg>

Even with --pretty, this becomes foobarbaz.

Expected behavior
foobar baz

Desktop (please complete the following information):

• SVGO 2.8.0
• Node.js 14.9.3

Additional context
I've narrowed it down to:

svgo/lib/parser.js

Line 228 in a9834ef

value: text.trim(),

I didn't check in detail, but presumably, String#trim() will remove any kind of Unicode whitespace, and there's quite a lot of variety there. If a space is non-breaking, I don't think SVGO should touch it.

Suggested fixes:

• Replace String#trim() with something that only trims [ \t\r\n].
• Add HTML elements to textElems so the else doesn't get hit.
• Don't trim anything inside <foreignObject> to avoid implementing an entire HTML parser.

[fasterthanlime]

I've been hit by this in the year of our bard 2024 and the suggested fixes make sense to me, too.