Allow uninstalling DMRH when not used for management

Bug: 360807442
Test: btest a.d.c.DevicePolicyManagementRoleHolderTest
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:da522df80568c158fe30896f9a571d05556ee51a)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:28a7456fab08d11e1e95a50abc23a0ade6edede2)
Merged-In: I023f78cef11fb7e8e9a92e2896cf94c9fcd1113b
Change-Id: I023f78cef11fb7e8e9a92e2896cf94c9fcd1113b
1 file changed