montpellier: use background image for "required authentication" forms (#9180)

static/montpellier/_custom.scss

@@ -743,3 +743,18 @@ div#welcome h3 {
 	text-align: center;
 	font-size: 150%;
 }
+
+
+/* it's not possible to use :after here as it's already overloaded to be used
+ * for the category>formdef overlay; so we cancel :after and use a simple
+ * background image.
+ */
+li.required-authentication a:after {
+	content: "";
+}
+
+li.required-authentication a {
+	background-image: url(cle.png);
+	background-repeat: no-repeat;
+	background-position: 98% 50%;
+}