Navigation: Fix page list issues in overlay (#37444)

* Fix padding for page list in overlay menu.

* Fix vertical stacking of menu containers.

packages/block-library/src/navigation/style.scss

@@ -432,6 +432,8 @@ button.wp-block-navigation-item__content {
 			// as a column.
 			display: flex;
 			flex-direction: column;
+			flex-wrap: nowrap;
+
 			// Inherit alignment settings from container.
 			align-items: var(--layout-justification-setting, inherit);
 
@@ -460,20 +462,19 @@ button.wp-block-navigation-item__content {
 				// Position and style.
 				position: static;
 				border: none;
-				padding-left: 32px;
-				padding-right: 32px;
+				padding-left: 2em;
+				padding-right: 2em;
 			}
 
 			// Space unfolded items using gap and padding for submenus.
 			.wp-block-navigation__submenu-container,
 			.wp-block-navigation__container {
 				gap: var(--wp--style--block-gap, 2em);
+			}
 
-				// Apply top padding to nested submenus.
-				.wp-block-navigation__submenu-container,
-				.wp-block-navigation__container {
-					padding-top: var(--wp--style--block-gap, 2em);
-				}
+			// Apply top padding to nested submenus.
+			.wp-block-navigation__submenu-container {
+				padding-top: var(--wp--style--block-gap, 2em);
 			}
 
 			// A default padding is added to submenu items. It's not appropriate inside the modal.
@@ -581,14 +582,12 @@ button.wp-block-navigation-item__content {
 // The menu adds wrapping containers.
 .wp-block-navigation__responsive-close {
 	width: 100%;
-	height: 100%;
 }
 
 .is-menu-open .wp-block-navigation__responsive-close,
 .is-menu-open .wp-block-navigation__responsive-dialog,
 .is-menu-open .wp-block-navigation__responsive-container-content {
 	box-sizing: border-box;
-	height: 100%;
 }
 
 .wp-block-navigation__responsive-dialog {