Fix broken and flaky VTS tests

1. nvResetConfig takes some time to reset the modem, causing subsequent
   tests to fail with a timeout since the modem is unavailabe.
   Add a timeout after nvResetConfig to allow the modem to be up again
   before running the next test.
2. Remove invalid errors for start/stopKeepalive. These tests should
   fail due to invalid arguments, so remove NONE as a possible error.
   RADIO_NOT_AVAILABLE should also be removed.
3. Fix incorrect startNetworkScan_InvalidInterval tests, since we only
   check the interval when the scan type is PERIODIC.
4. Save and reset the previous allowed network type bitmap after the
   test. Combine get/set into one test that tests both behaviors.
5. Fix checks for MCC/MNC in getDataRegistrationState

Bug: 277626718
Bug: 240953393
Bug: 264913330
Bug: 259674407
Bug: 242801688
Test: atest VtsHalRadioTargetTest
Change-Id: Ic7188f9d8ccfcd90d844b45e3b370a3be3c515d6
Merged-In: Ic7188f9d8ccfcd90d844b45e3b370a3be3c515d6