style: update button group class for improved layout in NotificationAgents.page and default-base.css

- Changed the class from 'button-group' to 'buttons-spaced' in NotificationAgents.page for better spacing.
- Updated the corresponding CSS class in default-base.css to maintain consistent styling.

emhttp/plugins/dynamix/NotificationAgents.page

@@ -213,7 +213,7 @@ foreach ($xml_files as $xml_file) {
     <dl>
         <dt>&nbsp;</dt>
         <dd>
-            <div class="button-group">
+            <div class="buttons-spaced">
               <input type="submit" value="<?= _("Apply") ?>" onclick="prepareService(this, '<?= $name ?>')" disabled>
               <input type="button" value="<?= _("Done") ?>" onclick="done()">
 

emhttp/plugins/dynamix/styles/default-base.css

@@ -198,7 +198,7 @@ a.button,
 
 /* necessary evil until we re-write button styles */
 .buttons-no-margin,
-.button-group {
+.buttons-spaced {
     display: flex;
     flex-wrap: wrap;
     gap: 1.2rem;