Squashed: Revert support for a provisioning apn

Revert "Telephony: check if the provisioning apn is actually empty before"

This reverts commit 8bd3c8f190802eea210b6efb0c435c7a1aeb8d2e.

Revert "Add support for a provisioning apn."

This reverts commit b76281167cf8763188ecc0e5158679d3ab43c36e.