Add dumy onReadConfig function override, to satisfiy changes I made.

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/casiogb6900/CasioGB6900DeviceSupport.java

@@ -767,6 +767,11 @@ public class CasioGB6900DeviceSupport extends AbstractBTLEDeviceSupport {
 
     }
 
+    @Override
+    public void onReadConfiguration(String config) {
+
+    }
+
     @Override
     public void onTestNewFunction() {