Edit Branch Rules: Status Check: Create Add/Edit new status check drawer

Context

See [MVC] Branch Rules Editing (&8075 - closed) and Implement Status checks (#388130 - closed)

Tasks

• Click "Add status check", display "Add status check" drawer
  • When csaved, display toast "Status check added"
• When "Edit" clicked, display "Update status check" drawer
  • When change made and saved, display toast "Status check updated"
• Validate second field for URL presence

Mockups

Description	Mockup
Default view
Add status check
Update status check