Remove spreadString in favor of polyfilled Array.from

What does this MR do?

Remove spreadString in favor of polyfilled Array.from. Array.from is a drop-in replacement.

Are there points in the code the reviewer needs to double check?

We use this to split up astral symbols

// ["🖐", "🏿"]
Array.from('🖐🏿');

I have tested in IE11 which doesn't have any Array.from support natively but the polyfill seems to work great, https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/from#Browser_compatibility

Why was this MR needed?

No need to have an extra spreadString custom function.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Tests
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #29794 (closed)