route_to_stream pipeline function should throw error when message would be silently dropped

[waab76]

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.