[Chore]: Restrict fullfillment for non-completed Emily events

[MCJOHN974]

Chore - Restrict fullfillment for non-completed Emily events

1. Description

In current implementation only confirmed deposit requests can (from logical side of view) have a fulfillment attached to them. However we don't forbid to send update request with fulfillment and with not-completed status. We should change this, making Emily returning an error if it receives update for non-completed deposit with fulfillment.

Note: currently, Emily silently ignores fulfillment for non-completed events, so this PR is more about notifying request sender that they are doing something wrong, rather then caring about Emily state correctness. (However logically wrong requests still is a bad thing and it is nice to bail when we see them).

2. Why It's Necessary

We want Emily to report that this update request is invalid, instead of silently save it, dropping the fulfillment.

3. Execution Checklist

• Emily now bail on non-completed deposits with fulfillment
• Tests for this bailing