Continue receive flow on offer/invoice creation failure

[Camillarhi]

Continue receive flow when BOLT12 offer or BOLT11 invoice creation fails, logging errors but
allowing onchain BIP21 as fallback.

Fixes #476

[ldk-reviews-bot]

👋 Thanks for assigning @tnull as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

[tnull]

Looks good, but please also change the docs to match the new behavior. Also, can we add test coverage for this?

[Camillarhi]

Looks good, but please also change the docs to match the new behavior. Also, can we add test coverage for this?

Thanks, I will make this update

[Camillarhi]

Looks good, but please also change the docs to match the new behavior. Also, can we add test coverage for this?

Thanks, I will make this update

Hello @tnull, the docs and test coverage have been updated

[enigbe]

I've tested this and the changes LGTM.

[tnull]

LGTM, just a few nits basically.

You'll also need to run cargo fmt to make the CI happy.

[tnull]

LGTM