Resolve "Web IDE doesn't work for branches with slashes"

What does this MR do?

It URL encodes the branch name and through this, the Web IDE is able to work with branches with slashes.

Are there points in the code the reviewer needs to double check?

I would also suggest that we even pick this for 10.8 ?

Why was this MR needed?

So Branches with features work

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • 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
• Internationalization required/considered
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?

Closes #45530 (closed)