XWIKI-21842: The search bar takes too much width when folded

* Replaced the ScaleX transition with a width + padding one.

Note: This is a heavier implementation because layout needs to be recalculated multiple times, but we actually want layout to move around depending on the state of the search toggle, so it's worth it.

xwiki-platform-core/xwiki-platform-flamingo/xwiki-platform-flamingo-skin/xwiki-platform-flamingo-skin-resources/src/main/resources/flamingo/less/action-menus.less

@@ -121,8 +121,7 @@
     border-radius: 0;
     border: 0;
     min-width: 0;
-    transform-origin: 100% 50%;
-    transition: transform 300ms ease-in-out;
+    transition: width 300ms ease-in-out, padding 300ms ease-in-out;
     width: 200px; // we need to set a width in pixels otherwise the transition is not applied nicely
   }
 
@@ -144,7 +143,8 @@
     }
     // The input has no width (it's hidden basically, but we need to set the width to 0 to have the nice transition)
     & + #headerglobalsearchinput { // we need to be that specific to be applied
-      transform: scaleX(0);
+      width: 0;
+      padding: 0;
     }
   }
 }