feat: LangSwitchFlag marks active lang

src/QUI/Bricks/Controls/LanguageSwitches/Flags.html

 {assign var=siteLang value=$Project->getLang()}
-{assign var=siteLang value=$Project->getLang()}
 {assign var=all value=$this->getAttribute('all')}
 {assign var=path value=$this->getAttribute('flagFolderPath')}
 
@@ -9,10 +8,15 @@
     {foreach from=$langs item=lang}
     {if $all || $siteLang != $lang}
 
+    {assign var=activeLang value=''}
+    {if $siteLang == $lang}
+        {assign var=activeLang value='active'}
+    {/if}
+
     {if $Site->getId($lang)}
-    <a class="quiqqer-bricks-languageswitch-flag-entry" href="{url id=$Site->getId($lang) lang=$lang}">
+    <a class="quiqqer-bricks-languageswitch-flag-entry {$activeLang}" href="{url id=$Site->getId($lang) lang=$lang}">
     {else}
-    <a class="quiqqer-bricks-languageswitch-flag-entry" href="{url id=1 lang=$lang}">
+    <a class="quiqqer-bricks-languageswitch-flag-entry {$activeLang}" href="{url id=1 lang=$lang}">
     {/if}
 
         {if $this->getAttribute('showFlags')}