Allow connecting to an IS from address picker

This allows those who previously disconnected from an IS to either choose the
default IS or a custom one from Settings via the address picker dialog.

Part of https://github.com/vector-im/riot-web/issues/10619

res/css/views/auth/_AuthBody.scss

@@ -39,8 +39,7 @@ limitations under the License.
     a:link,
     a:hover,
     a:visited {
-        color: $accent-color;
-        text-decoration: none;
+        @mixin mx_Dialog_link;
     }
 
     input[type=text],

res/css/views/dialogs/_AddressPickerDialog.scss

@@ -67,3 +67,6 @@ limitations under the License.
     pointer-events: none;
 }
 
+.mx_AddressPickerDialog_identityServer {
+    margin-top: 1em;
+}