Fixed unnecessary new line in alert snippet

Before: In edit mode, creating an alert snippet would create an empty
new line at the begining of the snippet.

Author: Goaman

addons/website/views/snippets/s_alert.xml

@@ -2,9 +2,9 @@
 <odoo>
 
 <template id="s_alert" name="Alert">
-    <div class="s_alert s_alert_md alert alert-info w-100 clearfix" role="alert" data-vcss="001">
+    <div class="s_alert s_alert_md alert alert-info w-100 clearfix o-contenteditable-false" role="alert" data-vcss="001">
         <i class="fa fa-lg fa-info-circle fa-stack d-flex align-items-center justify-content-center me-3 p-2 rounded-1 s_alert_icon"/>
-        <div class="s_alert_content">
+        <div class="s_alert_content o-contenteditable-true">
             <p>Explain the benefits you offer. <br/>Don't write about products or services here, write about solutions.</p>
         </div>
     </div>