On create-course page: reset yearW to empty string when year < 2000

web/template/admin/admin_tabs/create-course.gohtml

@@ -3,7 +3,7 @@
 {{define "create-course"}}
     <div class="text-1 container mx-auto"
          x-data="{ tumonlineid: '', slug: '', title: '', year: '', yearW: '', semester: 'Wintersemester', numberAttendees: null, searchQuery: '', searchResults: [] , isSearchResultVisible: false}"
-        x-init="$watch('year',(value)=>{if(value<2000)return; yearW = (value%1000) + 1})">
+        x-init="$watch('year',(value)=>{ yearW = (value<2000) ? '' : (value%1000) + 1 })">
         <div class="min-w-screen flex items-center justify-center">
             <div class="w-full lg:w-5/6 p-3 bg-gray-100 dark:bg-secondary rounded dark:border dark:border-gray-500 shadow">
                 <h2 class="mb-0">Find your course from TUMOnline</h2>