[bug]: Don't allow unconfirmed Inputs for Channel Openings which are used/labeled by the sweeper subsytem.

[ziggie1984]

Make sure we don't use sweeper related unconfirmed outputs for channel openings. Because those Inputs are actively rebroadcasted leading to RBF situations. This is especially critical for zeroconf channels which could potentially RBFed without the operator of the Channel noticing leading to fractional reserve problems where the node operator allocates more funds into channels than he actually has.

[ziggie1984]

relates to #8540.