Add additional fields to RecommendationRequest.

- Add networkId and timestamp for the last user selected network

Bug: 34467596
Test: runtest --path core/tests/coretests/src/android/net/RecommendationRequestTest.java
Change-Id: Ic81c1beede1a643cd428b6e5c57ed430a6b1ccc0
Merged-In: Ic81c1beede1a643cd428b6e5c57ed430a6b1ccc0