pytest: initialize grpc_port value of LightningNode class with opti…

…on value before the daemon is configured

this is important since `LightningD` now disables the grpc plugin if the
`grpc_port` is set to None

contrib/pyln-testing/pyln/testing/utils.py

@@ -770,6 +770,7 @@ def __init__(self, node_id, lightning_dir, bitcoind, executor, valgrind, may_fai
         self.rc = 0
 
         # Ensure we have an RPC we can use to talk to the node
+        self.grpc_port = options.get("grpc-port") if options else None
         self._create_rpc(jsonschemas)
 
         self.gossip_store = GossipStore(Path(lightning_dir, TEST_NETWORK, "gossip_store"))
@@ -839,7 +840,7 @@ def _create_rpc(self, jsonschemas):
 
     def _create_grpc_rpc(self):
         from pyln.testing import grpc
-        self.grpc_port = reserve_unused_port()
+        self.grpc_port = self.grpc_port or reserve_unused_port()
         d = self.lightning_dir / TEST_NETWORK
         d.mkdir(parents=True, exist_ok=True)
 
@@ -862,7 +863,6 @@ def _create_grpc_rpc(self):
 
     def _create_jsonrpc_rpc(self, jsonschemas):
         socket_path = self.lightning_dir / TEST_NETWORK / "lightning-rpc"
-        self.grpc_port = None
 
         self.rpc = PrettyPrintingLightningRpc(
             str(socket_path),