Only replace updated cards after loading from db.

There are currently 2 ways a list of contextual cards can be updated:
1. through loader onFinishLoading
2. onContextualCardUpdated

We need to make the data handling logic consistent between the 2 paths.

Also changed some loops to stream for simplicity.

Change-Id: I242732e180a14092f5745271e5f63c18a6e482e0
Fixes: 115572494
Test: robotests