MSIM: Dummy subId related changes

Replace isActiveSubId() in some places where isValidSubscriptionId()
method used, this change is to filter out DUMMY subId value

Change access modifier of below method and enum to protected
 - handleSimLoaded()
 - EVENT_SIM_LOCKED_QUERY_ICCID_DONE

Change-Id: I768d6de927fc49a6cc5c06f2102b8688e6191c57
CRs-Fixed: 1034971