[bug]: creating an invoice with a negative expiry defaults to 86400 seconds

[bufo24]

Background

When creating an invoice using v1/taproot-assets/channels/invoice using a negative expiry value in seconds, I get an invoice with an expiry of 86400 seconds.

Your environment

tapd v0.8.0

• any other relevant environment details

Steps to reproduce

Make an invoice using this body:

{
	"asset_amount": "1000000",
	"group_key": "...",
	"invoice_request": {"expiry": -1}
}

Expected behavior

I would expect the RPC to throw an error, since it isn't possible to make an invoice with a negative expiry.