networkAgent.js: Make the WPS message smaller

Smaller in size and in font size, similar to the caption
used in the run dialog.

WPS is only added as a hint, it wasn't even mentioned in the
Gtk agent.

data/theme/cinnamon-sass/widgets/_dialogs.scss

@@ -39,6 +39,11 @@
   }
 
   .message-dialog-description { text-align: center; }
+
+  .message-dialog-caption {
+    @extend %caption; 
+    text-align: center;
+  }
 }
 
 // run dialog

js/ui/networkAgent.js

@@ -91,8 +91,8 @@ class NetworkSecretDialog extends ModalDialog.ModalDialog {
 
         if (flags & NM.SecretAgentGetSecretsFlags.WPS_PBC_ACTIVE) {
             let descriptionLabel = new St.Label({
-                text: _('Alternatively you can connect by pushing the “WPS” button on your router.'),
-                style_class: 'message-dialog-description',
+                text: _('You can also connect by pushing the “WPS” button on your router.'),
+                style_class: 'message-dialog-caption',
             });
             descriptionLabel.clutter_text.line_wrap = true;
             descriptionLabel.clutter_text.ellipsize = Pango.EllipsizeMode.NONE;