listsendpays: discriminate ongoing payment by groupid

A payment attempt in listpays is defined as pair (payment hash, group id).
If we query xpay for ongoing payments we must discriminate
using both values.

Fixes flaky test tests/test_pay.py:test_sendpay_grouping
```
FAILED tests/test_pay.py::test_sendpay_grouping - AssertionError: assert ['pending', 'pending', 'complete'] == ['failed', 'failed', 'complete']
```

Changelog-None

Signed-off-by: Lagrang3 <lagrang3@protonmail.com>

plugins/xpay/listpays.c

@@ -159,7 +159,8 @@ static void add_new_entry(struct plugin *plugin,
 
 	if (pm->state & PAYMENT_COMPLETE)
 		json_add_string(ret, "status", "complete");
-	else if (pm->state & PAYMENT_PENDING || attempt_ongoing(plugin, pm->payment_hash))
+	else if (pm->state & PAYMENT_PENDING ||
+		 attempt_ongoing(plugin, pm->payment_hash, pm->sortkey.groupid))
 		json_add_string(ret, "status", "pending");
 	else
 		json_add_string(ret, "status", "failed");

plugins/xpay/xpay.c

@@ -2510,13 +2510,15 @@ static struct payment *new_payment(const tal_t *ctx,
 	return payment;
 }
 
-bool attempt_ongoing(struct plugin *plugin, const struct sha256 *payment_hash)
+bool attempt_ongoing(struct plugin *plugin, const struct sha256 *payment_hash,
+		     u64 groupid)
 {
 	struct xpay *xpay = xpay_of(plugin);
 	const struct payment *payment;
 
 	list_for_each(&xpay->payments, payment, list) {
-		if (sha256_eq(&payment->payment_hash, payment_hash))
+		if (sha256_eq(&payment->payment_hash, payment_hash) &&
+		    payment->group_id == groupid)
 			return true;
 	}
 	return false;

plugins/xpay/xpay.h

@@ -7,6 +7,7 @@ struct plugin;
 struct sha256;
 
 /* Are we still attempting this payment?  If so, we won't list is as failed. */
-bool attempt_ongoing(struct plugin *plugin, const struct sha256 *payment_hash);
+bool attempt_ongoing(struct plugin *plugin, const struct sha256 *payment_hash,
+		     u64 groupid);
 
 #endif /* LIGHTNING_PLUGINS_XPAY_XPAY_H */