Remove payment secret workaround

[erickcestari]

Now that the payment secret is needed by both the writer and the reader, we should remove the ldk workaround

Closes #138

[morehouse]

I think we need to wait on this until CLN, LND (and others?) also reject such invoices.

Otherwise the fuzz test will be constantly failing.

[brunoerg]

I think we need to wait on this until CLN, LND (and others?) also reject such invoices.

What is the current state of it?

[erickcestari]

I think we need to wait on this until CLN, LND (and others?) also reject such invoices.

What is the current state of it?

The LND implementation will be completed in two phases: first, the initial phase must be merged, and only then will LND start enforcing the payment secret requirement in the second phase

https://github.com/lightningnetwork/lnd/pull/9752

The CLN is waiting for the new changes on bolts. https://github.com/ElementsProject/lightning/pull/8221

[brunoerg]

Update: CLN has removed it, now we're just waiting for LND.