[feature]: add taproot chan support to rbf-closer

[Roasbeef]

Is your feature request related to a problem? Please describe.

Today we don't allow the new RBF close feature to be activated with taproot channels, we'll error out on start up here:

lnd/server.go

Lines 615 to 624 in b01f4e5

	// For now, the RBF coop close flag and the taproot channel type cannot
	// be used together.
	//
	// TODO(roasbeef): fix
	if cfg.ProtocolOptions.RbfCoopClose &&
	cfg.ProtocolOptions.TaprootChans {
	return nil, fmt.Errorf("RBF coop close and taproot " +
	"channels cannot be used together")
	}

Describe the solution you'd like

We should fix this by adding the additional nonce logic needed to support taproot channels w/ the new rbf coop close flow. This is very similar to the nonce handling we use for the existing legacy close protocol.

The spec currently lacks a section detailing the changes to support the taproot channels, this comment is the current best source of truth for the protocol extension: lightning/bolts#1205 (comment).

Additional context

As a stop gap (as there's some spec work needed here), we should update this section to just create a normal chan closer if the channel is a taproot channel, and the RBF close feature is enabled:

lnd/peer/brontide.go

Lines 3321 to 3340 in b01f4e5

	// If the new RBF co-op close is negotiated, then we'll init and start
	// that state machine, skipping the steps for the negotiate machine
	// below.
	if p.rbfCoopCloseAllowed() {
	_, err := p.initRbfChanCloser(lnChan)
	if err != nil {
	return nil, fmt.Errorf("unable to init rbf chan "+
	"closer during restart: %w", err)
	}
	shutdownDesc := fn.MapOption(
	newRestartShutdownInit,
	)(shutdownInfo)
	err = p.startRbfChanCloser(
	fn.FlattenOption(shutdownDesc), lnChan.ChannelPoint(),
	)
	return nil, err
	}

[Abdulkbk]

As a stop gap (as there's some spec work needed here), we should update this section to just create a normal chan closer if the channel is a taproot channel, and the RBF close feature is enabled

Mentioning that this part has been addressed in #9669 in case anyone comes across.

[Roasbeef]

I also have a PR incoming shortly that implements this issue.