route_to_stream pipeline function silently dropping messages

## Expected Behavior
When `route_to_stream` is called for a paused stream and the `remove_from_default` argument is set, an exception should be raised to indicate that processing has failed.

## Current Behavior
When `route_to_stream` is called for a paused stream and the `remove_from_default` argument is set, the message will not be added to the target stream and it will be removed from the default stream, resulting in the message being silently lost.

## Possible Solution
Update `route_to_stream` logic to raise an error instead of silently dropping messages from all streams.