Fix end-of-lab grace period default

src/main/resources/templates/lab/create/components/advanced/lab.html

@@ -41,7 +41,9 @@
                     <input id="end-of-lab-gp-input" class="form-control"
                            min="0" max="180"
                            type="number"
-                           th:field="*{eolGracePeriod}"/>
+                           name="eolGracePeriod"
+                           value="15"
+                           required/>
                 </div>
             </div>
         </div>