Add wiki front matter title

What does this MR do and why?

Add wiki front matter title

related to issue #30758 (comment 1054544532)

Screenshots or screen recordings

How to set up and validate locally

1. enable ff wiki_front_matter and ff wiki_front_matter_title
2. create a new wiki page or edit a exist wiki page
3. add Front Matter with title in wiki content
4. save - it is saved correctly
5. back to wiki page, it should display the front matter title.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.