[pm] forbid deletion of protected packages

BUG: 242996180
Test: adb shell pm uninstall --user 0 com.google.android.apps.work.oobconfig
Test: Verified with the command above. Before this CL, the package can
be deleted. After this CL, the deletion will fail.
Change-Id: I986e4d9661a645da28537a5390214cae837c77d5

Change-Id: Iba408e536b340ea5d66ab499442c0c4f828fa36f