Add default channel acceptor

- Implemented a default channel acceptor script for the channel acceptor in 'channel_acceptor.go'. If no accept script is provided, the default script is set to "continue".
- Updated 'cln_plugin.go' to include a new DefaultChannelAcceptorScript variable with an empty string default value.
- Updated the handleGetManifest function to include DefaultChannelAcceptorScript as a default for the 'channelAcceptScript' field.

cln_plugin/cln_plugin.go

@@ -23,7 +23,8 @@ const (
 )
 
 var (
-	DefaultSubscriberTimeout = "1m"
+	DefaultSubscriberTimeout     = "1m"
+	DefaultChannelAcceptorScript = ""
 )
 
 const (
@@ -259,6 +260,7 @@ func (c *ClnPlugin) handleGetManifest(request *Request) {
 					Name:        channelAcceptScript,
 					Type:        "string",
 					Description: "starlark script for channel acceptor.",
+					Default:     &DefaultChannelAcceptorScript,
 				},
 			},
 			RpcMethods: []*RpcMethod{