Add support for ApnSetting.TYPE_OEM_PAID and OEM_PRIVATE

Bug: 366194627
Test: m
Test: manually add oem_paid APN to telephony.db and verify if shows up
      in APN editor
Flag: com.android.internal.telephony.flags.oem_paid_private
Change-Id: Ida8f6f5712f49caa3172119c547b7ee17e41c12e