Implement option to remove profile owner on primary user

When test dpc is set as profile owner on primary user it cant be removed because the option to remove device owner is grayed out
Please implement it

[jscott1989]

I believe this is actually a limitation of Android - Profile Owners on the primary user are not able to remove themselves.

Assuming testOnly is set as true on your build - you can remove it using adb.

We won't be able to make changes to this in Android U but it might tie into some things we're doing in the next version after that.