[opayen]

That won't happen because 3rd party apps cannot have the READ_PRIVILEGED_PHONE_STATE permission.

[kllrnohj]

Correct: https://android.googlesource.com/platform/frameworks/base/+/...

The permission is signature|privileged. Only apps signed with the same keys as the OS itself or pre-installed in /system/priv-app can get the permission at all.