Fix backend preview

Author: kohlercode

ContentBlocks/ContentElements/bootstrap-alert/templates/backend-preview.html

@@ -1,6 +1,7 @@
 <div class="alert alert-{data.bootstrap_theme_color}{f:if(condition: data.bootstrap_dismissible, then: ' alert-dismissible fade show')}">
+    <div class="fw-bold">{data.header}</div>
     <f:transform.html>{data.bodytext}</f:transform.html>
-    <f:if condition="{data.sk_bootstrapalert_dismissible}">
+    <f:if condition="{data.bootstrap_dismissible}">
         <button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>
     </f:if>
 </div>