Fix rendering of highlighted URLs

[asdf-a11]

Add compact, short information about your PR for easier understanding:

• Goal of the PR
  Fixes Highlighting the URL text in the "Open URL" window causes buggy text rendering #16246 where highlighting a url would cause some characters to appear and others to dissapear.
• How does the PR work?
  In the GUIEditBoxWithScrollBar::draw method it creates a copy of the string to be drawn and in this copy removes rich text formatting information and then draws the new string.
• Does it resolve any reported issue?
  Highlighting the URL text in the "Open URL" window causes buggy text rendering #16246
• Does this relate to a goal in the roadmap?
• If not a bug fix, why is this PR needed? What usecases does it solve?

To do

This PR Ready for Review

How to test

To test use infomation provided in #16246 issue.

[appgurueu]

I don't think that throwing away the color info can produce a clean solution.

The cleanest solution is probably to utilize EnrichedString properly.

[appgurueu]

You're (incorrectly) reimplementing unescape_enriched (found in src/util/string.h) here.

[appgurueu]

You shouldn't just throw away the color here. (And if we wanted to throw away the color, which we don't, we would do that way earlier, during construction or when the text is set.)

[asdf-a11]

Yes I would agree. (I am still getting familiar with the code base) So is there not already a string class that handles colour information and you are proposing to replace core::stringw with a new rich text class for all text rendering?

[appgurueu]

So is there not already a string class that handles colour information

Yes, there is EnrichedString. (Initially I had misremembered what exactly that did, but it does pretty much what we need: Separate a string with color (and translation) escapes into plain text and color info.)

and you are proposing to replace core::stringw with a new rich text class for all text rendering?

Yes, replacing core::stringw with EnrichedString for the text. This could become a bit nasty due to the inheritance (requiring you to touch more classes than you'd like to).