Migrate to TetherOffloadRuleParcel in IpServer

The netd tethering offload IPCs are changing from taking a list
of primitives to taking a TetherOffloadRuleParcel. Modify their
only caller.

Bug: 140541991
Test: atest IpServerTest
Merged-In: I83718c80ef9d31199c87021b4dd5821717fd5ba5
Change-Id: I83718c80ef9d31199c87021b4dd5821717fd5ba5