Fix: AMC overflow menu initial CSS and SSR icons

When advanced mobile contributions is enabled and the overflow menu is
shown:

- The initial state should have no transition. This prevents the menu
  from flickering initially. Move the transition to the checked state
  only.

- The icons should be available for server-side rendered HTML without
  JavaScript. Add wikimedia.ui to the SSR modules.

Bug: T216418#5129152
Change-Id: I3b91f6cdefd4b727c2fb512272d8c4282af632bf

includes/skins/SkinMinerva.php

@@ -1221,7 +1221,8 @@ class SkinMinerva extends SkinTemplate {
 			'mediawiki.hlist',
 			'mediawiki.ui.icon',
 			'mediawiki.ui.button',
-			'skins.minerva.icons.images'
+			'skins.minerva.icons.images',
+			'wikimedia.ui'
 		];
 		if ( $title->isMainPage() ) {
 			$styles[] = 'skins.minerva.mainPage.styles';

resources/skins.minerva.base.styles/pageactions.less

@@ -134,12 +134,16 @@
 	box-shadow: 0 5px 17px 0 rgba( 0, 0, 0, 0.24 ), 0 0 1px @colorGray10;
 	border-radius: @borderRadius;
 	//
-	// Animate menu visibility, opacity, and translation changes in and out. Visibility must be
-	// animated since it's a boolean and nothing can be seen in the hidden state.
 	visibility: hidden;
 	opacity: 0;
 	transform: translateY( -8px );
-	.transition( visibility .1s ease-in-out, opacity .1s ease-in-out, transform .1s ease-in-out; );
+
+	// Animate menu visibility, opacity, and translation changes in and out. Visibility must be
+	// animated since it's a boolean and nothing can be seen in display hidden. Visibility itself
+	// cannot be animated as it causes a flash on page load in Chromium due to
+	// https://bugs.chromium.org/p/chromium/issues/detail?id=332189. The effect is that the menu is
+	// animated in but not animated out.
+	.transition( opacity .1s ease-in-out, transform .1s ease-in-out; );
 }
 
 .toolbar-overflow-menu__list-item {