Allow REQUEST_NOT_SUPPORTED as an error for startNetworkScan

We are trying to tighten the APIs. However for this case since the
documentation was not updated, we are allowing NOT_SUPPORTED for
now and will be cleaned up in a later release.

Test: run vts -m VtsHalRadioV1_2Target
Bug: 110118713
Merged-In: Id9dd3d7bac99bed36ceb9c906189f1fea78d5a2c
Change-Id: Id9dd3d7bac99bed36ceb9c906189f1fea78d5a2c
(cherry picked from commit a7587b5a)