Remove getNeighboringCell API

Remove the obsolete getNeighboringCell API for callers
targeting Q or higher SDK. This API was fully
superceded by getAllCellInfo in KitKat, and
maintaining it results in battery drain because calls
to this API resulted in unrestricted modem calls.

For legacy support, this API now routes to the newer
CellInfo mechanism, which stems the battery drain but
further emphasizes the redundancy. Thus, removing this
is the best possible outcome for maintainers, users and
OEMs.

Bug: 62490173
Test: compilation; atest CtsPermissionTestCasesSdk28
Change-Id: I8aa806bfcad2ceefc9dfbff58c0ce48d5a3cab5b