feature: use +100 staging bit for taproot channels

In this commit, we carry out a new notion introduced during a recent
spec meeting to use a feature bit plus 100 before the feature has been
finalized in the spec.

We split into the Final and Staging bits.

feature/manager.go

@@ -176,8 +176,8 @@ func newManager(cfg Config, desc setDesc) (*Manager, error) {
 			raw.Unset(lnwire.ShutdownAnySegwitRequired)
 		}
 		if cfg.NoTaprootChans {
-			raw.Unset(lnwire.SimpleTaprootChannelsOptional)
-			raw.Unset(lnwire.SimpleTaprootChannelsRequired)
+			raw.Unset(lnwire.SimpleTaprootChannelsOptionalStaging)
+			raw.Unset(lnwire.SimpleTaprootChannelsRequiredStaging)
 		}
 
 		for _, custom := range cfg.CustomFeatures[set] {