Prevent re-linkifying links in blobs

What does this MR do?

This is my second attempt (first one was !19464 (merged)) to fix #35120 (closed), an issue where client-side linkifying of text in blobs (e.g. https://example.com becomes <a href="https://example.com">https://example.com</a>) would break server-side generated links.

This MR uses a more advanced approach compared to the first one (which was simply changing the regex to detect links) using the parsed HTML DOM to apply the linkification only to text nodes not part of an a tag.

Note that the original MR (!18305 (merged)) is currently being was reverted (!19887 (merged)), so once this MR gets approved and all other bugs with the linkification are fixed (if there are any) re-reverting the MR / cherry-picking the old commits would be required.

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all some supported browsers (Tested in Chrome, FF, Edge)

Closes #35120 (closed)