We will not add a buffer to the chan policy for blinded paths in case
the sender amount violates the minHTLC restriction in the first place.
Moreover we disgard a route fast if the payment amount is smaller than
the minHTLC along the route.
Removes a check where we would NOT allow to create a blinded invoice
with an expiry (invoice expiry in seconds considered as block time)
lower than the min_final_ctlv_delta.
In this commit, we adjust BuildBlindedPaymentPaths to only error out
completely if none of the paths it received from FindRoutes resulted in
a usable blinded path.
This commit introduces more sophisticated code for selecting dummy hop
policy values for dummy hops in blinded paths.
For the case where the path does contain real hops, the dummy hop policy
values are derived by taking the average of those hop polices. For the
case where there are no real hops (in other words, we are the
introduction node), we use the default policy values used for normal
ChannelUpdates but then for the MaxHTLC value, we take the average of
all our open channel capacities.
