Multiple Ui improvements (#7029)

* PLT-7119 - Updating headings on compact view

* PLT-7103 - Removing line below channel intro

* PLT-7112 - Fixing system console banner

* PLT-7144 - Adding ellipsis to system console boxes

* PLT-7181 - Changing channel header opacity

* PLT-6899 - Updating unread bar

* Updating margin for new messages indicator

webapp/components/admin_console/cluster_settings.jsx

@@ -120,12 +120,12 @@ export default class ClusterSettings extends AdminSettings {
             <SettingsGroup>
                 {configLoadedFromCluster}
                 {clusterTableContainer}
-                <p>
+                <div className='banner'>
                     <FormattedMessage
                         id='admin.cluster.noteDescription'
                         defaultMessage='Changing properties in this section will require a server restart before taking effect. When High Availability mode is enabled, the System Console is set to read-only and can only be changed from the configuration file unless ReadOnlyConfig is disabled in the configuration file.'
                     />
-                </p>
+                </div>
                 {warning}
                 <BooleanSetting
                     id='Enable'