use `required` property for array items

gadget_json_generated_form_child.js

@@ -142,6 +142,7 @@
         }
         return form_gadget.renderForm({
           type: options.type,
+          required: options.required,
           schema: options.schema_part,
           schema_path: options.schema_path,
           document: options.default_dict,
@@ -495,7 +496,8 @@
                   parent_type: 'array',
                   schema_path: schema_path + '/items',
                   schema_part: schema_arr,
-                  default_dict: json_document[i]
+                  default_dict: json_document[i],
+                  required: i < minItems
                 })
               )
               .push(div_append);
@@ -511,7 +513,8 @@
                   gadget: gadget,
                   parent_type: 'array',
                   schema_path: schema_arr[0].schema_path,
-                  schema_part: schema_arr[0].schema
+                  schema_part: schema_arr[0].schema,
+                  required: true
                 })
               )
               .push(div_append);