Finalizers send Freeze message before blocks they bake

**Bug Description**

When a finalizer bakes a block that is eligible for finalization, the finalizer generates and sends a Freeze message nominating the baked block before transmitting the block itself. This is not ideal, as we should expect a Freeze message that refers to an unknown block to trigger a catch-up with the sending peer, which should be avoided in normal operation. However, in fact, such messages are relayed and do not trigger a catch-up. Once the block is received, the finalization protocol is able to interpret the Freeze message as a valid nomination.

**Steps to Reproduce**

Run a node with debug level logging.

**Expected Result**

Do not observe Afgjort log messages of the form: Message refers to unjustified block; catch-up required.

**Actual Result**

Such log messages routinely occur.

**Versions**
- Software Version: all
- OS: all