Allow wiki pages with +<> characters in title to be saved

What does this MR do?

This MR fixes a bug that prevents wiki pages with +<> chars in the title from being saved.

A page's title and url_path properties are returned from Gitaly with any +<> characters changed to -.

This meant that previously the comparison within #title_changed? would inaccurately always return true when the title contained +<> characters, as the old title would be parsed to my page (after unhyphenization) while the new title would be my+page.

A wiki page's path property is returned from Gitaly these characters preserved. When we remove the extension we can use in place of the previous url_path to allow the #title_changed? method to support pages with +<> characters in its title.

• Issue: #218230 (closed)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done