feat: lnd_rest allow self payments (#2760)

* Update lndrest.py

- added the ability to receive self payments on the node

[issue] You have to enable circular payment on lnd.conf. Note that lnd.conf doesn't allow allow_self_payment parameter, that is why is necessary to define that on transaction.

* feat: add LND rest `"allow_self_payment"` option

---------

Co-authored-by: Vlad Stan <stan.v.vlad@gmail.com>

lnbits/wallets/lndrest.py

@@ -2,7 +2,7 @@ import asyncio
 import base64
 import hashlib
 import json
-from typing import AsyncGenerator, Dict, Optional
+from typing import Any, AsyncGenerator, Dict, Optional
 
 import httpx
 from loguru import logger
@@ -168,9 +168,15 @@ class LndRestWallet(Wallet):
         lnrpc_fee_limit["fixed_msat"] = f"{fee_limit_msat}"
 
         try:
+            json_: dict[str, Any] = {
+                "payment_request": bolt11,
+                "fee_limit": lnrpc_fee_limit,
+            }
+            if settings.lnd_rest_allow_self_payment:
+                json_["allow_self_payment"] = 1
             r = await self.client.post(
                 url="/v1/channels/transactions",
-                json={"payment_request": bolt11, "fee_limit": lnrpc_fee_limit},
+                json=json_,
                 timeout=None,
             )
             r.raise_for_status()