Add invoice_amount_sat to check_hold_invoice response

Adds an additional value to the `check_hold_invoice` cli command: `invoice_amount_sat` which returns the requested amount value of the hold invoice.

Co-authored-by: ghost43 <somber.night@protonmail.com>

electrum/commands.py

@@ -1489,8 +1489,10 @@ class Commands(Logger):
             amount_sat = amount_msat // 1000
         result = {
             "status": status,
-            "amount_sat_received": amount_sat
+            "received_amount_sat": amount_sat,
         }
+        if info is not None:
+            result["invoice_amount_sat"] = (info.amount_msat or 0) // 1000
         return result
 
     @command('w')