fix(gui): Disable preview as for low-privilege users

fix #170

Signed-off-by: Pranav C <61551451+pranavxc@users.noreply.github.com>

packages/nc-gui/components/ProjectTreeView.vue

@@ -461,7 +461,7 @@
           <!--          </v-list>-->
           <!--          <v-divider></v-divider>-->
 
-          <v-list dense>
+          <v-list dense v-if="_isUIAllowed('previewAs') || previewAs">
             <v-list-item>
               <!-- Preview as -->
               <span class="body-2 grey--text">{{ $t('treeview.preview_as') }}</span>