[JENKINS-75853] - Remove active look of hamburger button (#10804)

Author: krisstern

core/src/main/resources/lib/layout/header/actions.jelly

@@ -30,7 +30,7 @@
       </j:forEach>
     </j:set>
     <j:if test="${hamburgerEntries.length() gt 0}">
-      <l:overflowButton icon="symbol-menu-hamburger" id="header-more-actions">
+      <l:overflowButton icon="symbol-menu-hamburger" id="header-more-actions" clazz="jenkins-button--tertiary">
         <j:out value="${hamburgerEntries}" />
       </l:overflowButton>
     </j:if>