Ensure install packages app op is in place.

Sometimes the test fails because the app op gets removed from the
package. Not sure why it is nondeterministic.

Fixes: 321893594
Test: atest CtsDevicePolicyManagerTestCases:com.android.cts.devicepolicy.MixedManagedProfileOwnerTest#testPackageInstallUserRestrictions
Change-Id: I5be068c80fa8bedb4e1446e3c65afad873874e6c