Fixed LanguageSelector styling for IE to not show the native combobox

arrow in addition to our custom one

java/com.sap.sse.gwt/src/com/sap/sse/gwt/client/controls/languageselect/LanguageSelector.ui.xml

@@ -30,6 +30,9 @@
             background-position: right center;
             background-repeat: no-repeat;
         }
+        .languageSelection::-ms-expand {
+            display: none;
+        }
     </ui:style>
     <g:FlowPanel tag="span">
         <g:InlineLabel ui:field="labelUi" addStyleNames="{style.label}"/>