Fix transaction pool event sending

This pr fixes a bug with the transaction pool not sending certain events
like finalized and also fixes the order of events. The problem with the
finalized event was that we did not extracted pruned extrinsics if there
were not ready transactions in the pool. However this is wrong, if we
have a re-org, a tx is clearly not ready anymore and we still need to
send a pruned event for it because it is in a new block included. This
also lead to sending "ready" events and tx being re-validated. The
listener also only send the "finalized" event if it has seen a block as
being included, which did not happen before with the old code.

The second fix of the pr is the order of events. If we prune and retract the
same transaction in the same block, we first need to send the "retract"
event and after that the "pruned" event, because finalization takes
longer and this would lead to the UI showing "retract" while it actually
is included.