VIVO-315: add error message for missing type selection

languages/example/themes/wilma/i18n/all_es.properties

@@ -841,3 +841,4 @@ no_linked_author = ningún editor vinculados
 remove_editor_link = desconecte la conexión de editor
 add_an_editor = Agregar uno Editor
 add_editor = Agregar Editor
+please_select_type = Por favor Seleccione un tipo de la lista desplegable.

productMods/templates/freemarker/edit/forms/addRoleToPersonTwoStage.ftl

@@ -106,7 +106,10 @@ Set this flag on the input acUriReceiver where you would like this behavior to o
     	        </#if>
 	        </#if>
         </#list>
-        <#--Checking if Name field is empty-->
+        <#--Checking if Type, Name and Role fields are empty-->
+         <#if lvf.submissionErrorExists(editSubmission, "roleActivityType")>
+ 	        ${i18n().please_select_type}<br />
+        </#if>
          <#if lvf.submissionErrorExists(editSubmission, "activityLabel")>
  	        ${i18n().select_or_enter_name}<br />
         </#if>

themes/wilma/i18n/all.properties

@@ -859,3 +859,4 @@ no_linked_author = no linked editor
 remove_editor_link = remove editor link
 add_an_editor = Add an Editor
 add_editor = Add Editor
+please_select_type = Please select a type from the drop-down list.