Remove mobile provision design out from connectivity service

In order to support ConnectivityService mainline, module should
not use hidden APIs. The logic to get mobile provision is moved
to telephony surface since it's only used by telephony.
Hence, remove the design out from Connectivity.

Bug: 175177794
Test: atest FrameworksNetTests
Change-Id: Ic3082fc1c4d7ac998f4e4cff1351e6829d500924