EM24: drop kWh(-) export register, not available on all devices (#31736)

templates/definition/meter/cg-em24.yaml

@@ -24,7 +24,8 @@ render: |
   {{- if ne .usage "pv" }}
   power: Power
   energy: Import
-  returnenergy: Export
+  # removed per https://github.com/evcc-io/evcc/issues/31143
+  # returnenergy: Export
   currents:
     - CurrentL1
     - CurrentL2
@@ -35,7 +36,8 @@ render: |
     - PowerL3
   {{- else }}
   power: -Power
-  energy: Export
+  # removed per https://github.com/evcc-io/evcc/issues/31143
+  # energy: Export
   returnenergy: Import
   currents:
     - -CurrentL1