Revert "Add configs for ePDG"

This reverts commit 81a4f4ee.

Reason for revert: b/149531704  IKE @SystemApi constants re-exposed (duplicate) as Public API
Bug that introduced the original change(ag/9987427): b/140873586

Bug: 149531704
Change-Id: I7d521269085a5937bd9252438571d5d45f40a1b2