Remove async payments cfg flag

We were previously cfg-gating all async payments code to not have a
half-working public API, but now that async receive is usable go ahead and
remove the gating. Paying as an async sender is not yet supported.

Author: valentinewallace

Cargo.toml

@@ -66,6 +66,5 @@ check-cfg = [
     "cfg(taproot)",
     "cfg(require_route_graph_test)",
     "cfg(splicing)",
-    "cfg(async_payments)",
     "cfg(simple_close)",
 ]

lightning/src/events/mod.rs

@@ -1628,7 +1628,6 @@ pub enum Event {
 	///
 	/// [`ChannelManager::blinded_paths_for_async_recipient`]: crate::ln::channelmanager::ChannelManager::blinded_paths_for_async_recipient
 	/// [`ChannelManager::set_paths_to_static_invoice_server`]: crate::ln::channelmanager::ChannelManager::set_paths_to_static_invoice_server
-	#[cfg(async_payments)]
 	PersistStaticInvoice {
 		/// The invoice that should be persisted and later provided to payers when handling a future
 		/// [`Event::StaticInvoiceRequested`].
@@ -1676,7 +1675,6 @@ pub enum Event {
 	/// [`ChannelManager::set_paths_to_static_invoice_server`]: crate::ln::channelmanager::ChannelManager::set_paths_to_static_invoice_server
 	/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 	/// [`ChannelManager::send_static_invoice`]: crate::ln::channelmanager::ChannelManager::send_static_invoice
-	#[cfg(async_payments)]
 	StaticInvoiceRequested {
 		/// An identifier for the recipient previously surfaced in
 		/// [`Event::PersistStaticInvoice::recipient_id`]. Useful when paired with the `invoice_id` to
@@ -2123,13 +2121,11 @@ impl Writeable for Event {
 					(8, former_temporary_channel_id, required),
 				});
 			},
-			#[cfg(async_payments)]
 			&Event::PersistStaticInvoice { .. } => {
 				45u8.write(writer)?;
 				// No need to write these events because we can just restart the static invoice negotiation
 				// on startup.
 			},
-			#[cfg(async_payments)]
 			&Event::StaticInvoiceRequested { .. } => {
 				47u8.write(writer)?;
 				// Never write StaticInvoiceRequested events as buffered onion messages aren't serialized.
@@ -2711,10 +2707,8 @@ impl MaybeReadable for Event {
 				}))
 			},
 			// Note that we do not write a length-prefixed TLV for PersistStaticInvoice events.
-			#[cfg(async_payments)]
 			45u8 => Ok(None),
 			// Note that we do not write a length-prefixed TLV for StaticInvoiceRequested events.
-			#[cfg(async_payments)]
 			47u8 => Ok(None),
 			// Versions prior to 0.0.100 did not ignore odd types, instead returning InvalidValue.
 			// Version 0.0.100 failed to properly ignore odd types, possibly resulting in corrupt