Strip tags instead escaping on 'Commit#title' note

Further explained on https://gitlab.com/gitlab-org/gitlab-ce/issues/37616#note_40487829.

Instead escaping all chars before persisting the Commit#title on a Note this MR makes it just strip tags and avoid HTML being evaluated when showing the commit notes.

Commits list:

Discussion notes:

And for the example text on the description of this issue:

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together

What are the relevant issue numbers?

Closes #37616