Use Codex styles for buttons in language overlay

* Replace all instances of mw-ui markup with Codex markup
* Use @wikimedia/codex as it is available in 1.39
and codex-search-styles is not.

Bug: T340255
Change-Id: Id85cf3b4af782c0d93bfa3bed5f3e6cbed856f1b

resources/css/ext.uls.displaysettings.less

@@ -9,7 +9,8 @@
 .uls-button-group {
 	display: inline-block;
 	position: relative;
-	padding: 0;
+	// The 1px are needed to handle overflow in .cdx-button-group in 1.39
+	padding: 1px 0 0 1px;
 	left: -20px;
 	z-index: 1;
 }

resources/css/ext.uls.inputsettings.less

@@ -96,8 +96,8 @@
 	}
 }
 
-.uls-input-settings-inputmethods-list .mw-ui-radio {
-	display: block;
+.uls-input-settings .cdx-radio {
+	position: relative;
 }
 
 .uls-ime-notification-bubble .link {

resources/css/ext.uls.languagesettings.less

@@ -130,14 +130,20 @@
 	margin-left: 15px;
 }
 
+// This can be removed when 1.39 support is dropped.
+.uls-input-settings-inputmethods-list .cdx-radio__label,
+.checkbox.cdx-checkbox__label {
+	padding-left: ~'calc(1.25em + 8px)';
+}
+
 .uls-ui-languages p,
 .checkbox {
 	color: @color-subtle;
 	font-size: 10pt;
 }
 
-/* mediawiki.ui does not have a pressed state style. */
-#languagesettings-panels .mw-ui-pressed {
+/* @todo: Amend to use Codex when 1.39 support is no longer needed. */
+#languagesettings-panels .uls-cdx-button-pressed {
 	background-color: @background-color-progressive--active;
 	color: @color-inverted;
 	border-color: @border-color-progressive--active;