chainntnfs/btcdnotify: correctly notify on confirmed rescan spends
chainntnfs/btcdnotify: correctly notify on confirmed rescan spends

This commit fixes a recently introduced bug in the btcdnotifier, where
we would skip all spend clients waiting for a confirmed spend in
txUpdates. The regular case where a spend is included in a new block was
correctly handled in onBlockConnected, but the txUpdates queue is also
used for confirmed spends during rescans, which we would miss. This
commit fixes that by checking if the tx update is confirmed or
unconfirmed, and acts accordingly.

aakselrod/lnd,aakselrod/lnd,LightningNetwork/lnd,LightningNetwork/lnd