Resolves error when using a bad formatted URL on "Pull from remote" & "Push to remote" sections

What does this MR do?

• Solves 500 error thrown when entering a bad formatted URL on "Pull from a remote repository" or "Push to a remote repository" throws an error.
• Include specs for different scenarios

Why was this MR needed?

Entering a bad formatted URL on "Pull from a remote repository" or "Push to a remote repository" throws an error. This Merge Request solves both scenarios.

Screenshots (if relevant)

With an invalid URL on 'Pull from a remote repository' section

With an invalid URL on 'Push to a remote repository' section

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• 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
• Internationalization required/considered
• If paid feature, have we considered GitLab.com plan and how it works for groups and is there a design for promoting it to users who aren't on the correct plan

What are the relevant issue numbers?

#833 (closed)