MDEV-12877 Wrong result from JSON native function.

        JSON_QUOTE return type set to be JSON.

mysql-test/r/func_json.result

@@ -696,3 +696,6 @@ SET @path = "$.\"\\u00e4\"";
 select @str, @path, JSON_EXTRACT(@str, @path);
 @str	@path	JSON_EXTRACT(@str, @path)
 {"\u00e4":"yes"}	$."\u00e4"	"yes"
+select json_array(5,json_query('[1,2]','$'));
+json_array(5,json_query('[1,2]','$'))
+[5, [1,2]]

mysql-test/t/func_json.test

@@ -349,3 +349,8 @@ SET @str = "{\"\\u00e4\":\"yes\"}";
 SET @path = "$.\"\\u00e4\"";
 select @str, @path, JSON_EXTRACT(@str, @path);
 
+#
+# MDEV-12877 Wrong result from JSON native function.
+#
+select json_array(5,json_query('[1,2]','$'));
+

sql/item_jsonfunc.h

@@ -101,6 +101,7 @@ class Item_func_json_query: public Item_func_json_value
 public:
   Item_func_json_query(THD *thd, Item *js, Item *i_path):
     Item_func_json_value(thd, js, i_path) {}
+  bool is_json_type() { return true; }
   const char *func_name() const { return "json_query"; }
   bool check_and_get_value(json_engine_t *je, String *res, int *error);
   Item *get_copy(THD *thd, MEM_ROOT *mem_root)