Migrate hidden API in IpConfigStore to formal API

IpConfiguration and StaticIpConfiguration are included
in framework-connectivity which cannot have external
hidden API usages dependencies on them. IpConfiguration
and StaticIpConfiguration provide builder and getter
methods for the fields of the objects which are formal APIs.
So, replace the usages in IpConfigStore with those formal
APIs to remove the dependencies.

Bug: 178777253
Test: FrameworksServicesTests:IpConfigStoreTest
Change-Id: Ie9e6af0efe2c39667bb8faa1e3a498b1f61e1432