Add Inverter Total Power to data mapping

Added the 9th value od the DATA mapping (it is the sum of the 3 prevpous ones, so you do not have to do an helper)

Author: nenone78

solax/inverters/x3_hybrid_g4.py

@@ -83,6 +83,7 @@ def response_decoder(cls):
             "Grid 1 Power": (6, Units.W, to_signed),
             "Grid 2 Power": (7, Units.W, to_signed),
             "Grid 3 Power": (8, Units.W, to_signed),
+            "Inverter Total Power": (9, Units.W, to_signed),
             "PV1 Voltage": (10, Units.V, div10),
             "PV2 Voltage": (11, Units.V, div10),
             "PV1 Current": (12, Units.A, div10),