foot gun: create_da_message should return DAVote

[ggutoski]

HotShot/crates/types/src/traits/election.rs

Lines 514 to 520 in f92e68a

	/// Create a message with a vote on DA proposal.
	fn create_da_message(
	&self,
	block_commitment: Commitment<TYPES::BlockType>,
	current_view: TYPES::Time,
	vote_token: TYPES::VoteTokenType,
	) -> CommitteeConsensusMessage<TYPES>;

Returns type CommitteeConsensusMessage<TYPES> even though all uses immediately match on DAVote variant. See for example here:

HotShot/crates/task-impls/src/da.rs

Lines 301 to 315 in f92e68a

	let message = self.committee_exchange.create_da_message(
	block_commitment,
	view,
	vote_token,
	);
	// ED Don't think this is necessary?
	// self.cur_view = view;
	if let CommitteeConsensusMessage::DAVote(vote) = message {
	debug!("Sending vote to the DA leader {:?}", vote.current_view);
	self.event_stream
	.publish(SequencingHotShotEvent::DAVoteSend(vote))
	.await;
	}

These uses have no error-handling for when the match fails, which could lead to nasty bugs in the future. Better to use the type system to ensure this can't happen at compile time. Just return a DAVote instead.

Same for create_vid_message.