Cannot mark Multibranch Pipeline as Favorite in Blue Ocean when no master branch

Summary: if there is no master branch, if you try to favourite a MB pipeline (vs a specific branch) it does incorrect things. It should work out what the default branch is (or ask user) or at least tell them to pick a branch... (latter is easiest).

If a user has favourited a MB pipeline folder in classic, blue ocean should ignore that.

Steps:

1. Click "New Item" and Create "Multibranch Pipeline" without branch "master".
2. Open Dashboard Jenkins. Check "Favorite" button for Multibranch Pipeline.
3. Open Jenkins Blue Ocean.
   Actual Result: New line for this job has been created in "Favorites" (grey colour). "Run" button hasn't worked.
4. Open Dashboard Jenkins -> this Multibranch Pipeline. Check "Favorite" button for any branch.
   E.R. = A.R.: No error. Favorites Job have displayed correctly in Jenkins Blue Ocean.
5. Disable "Favorite" for this job.
6. Open Jenkins Blue Ocean.
7. Click "Favorite" button for Multibranch Pipeline.
   Expected Result: Favorite label has been added. New line for this job has been created in "Favorites".
   Actual Result: Failed to load resource: the server responded with a status of 400 (Bad Request)

   {
       "message" : "no master branch to favorite",
       "code" : 400,
       "errors" : [ ]
   }
   

8. Disable "Favorite" for this job.
   Expected Result: Favorite label has been deleted.
   Actual Result: TypeError: undefined is not an object (evaluating 'favoriteToRemove._links')