3420380 fixed width for dropbutton in olivero

Closes #3420380

core/themes/olivero/css/components/dropbutton.css

@@ -29,7 +29,7 @@
 
 .dropbutton-widget {
   position: relative;
-  width: max-content;
+  width: 100%;
   height: var(--dropbutton--height);
   padding-inline-end: var(--dropbutton--height);
   border-radius: var(--dropbutton--border-radius);
@@ -162,4 +162,5 @@
 
 .dropbutton-wrapper.open .secondary-action {
   visibility: visible;
+  padding: 0 0.5625rem;
 }