Fixed assertion in pay plugin

This PR includes the fix discussed on PR #3855. This fix was tested with the use case described inside the issue and worked.

Fixes: #3855

Changelog-None

plugins/libplugin-pay.c

@@ -1622,7 +1622,8 @@ local_channel_hints_listpeers(struct command *cmd, const char *buffer,
 			spendsats = json_get_member(buffer, channel, "spendable_msat");
 			scid = json_get_member(buffer, channel, "short_channel_id");
 			dir = json_get_member(buffer, channel, "direction");
-			assert(spendsats != NULL && scid != NULL && dir != NULL);
+			if(spendsats == NULL || scid == NULL || dir == NULL)
+				continue;
 
 			json_to_bool(buffer, connected, &h.enabled);
 			json_to_short_channel_id(buffer, scid, &h.scid.scid);

tests/test_pay.py

@@ -3157,7 +3157,6 @@ def test_mpp_adaptive(node_factory, bitcoind):
     pprint(l1.rpc.paystatus(inv))
 
 
-@pytest.mark.xfail(strict=True)
 def test_pay_fail_unconfirmed_channel(node_factory, bitcoind):
     '''
     Replicate #3855.