By Radovan Stoklasa BRATISLAVA (Reuters) – Hassan Al-Khalaf, 11, clung to hope when he trekked across Ukraine by himself, safely reaching Slovakia after joining the masses of refugees escaping Russia’s invasion of their country. Hassan arrived in Slovakia in early March, drawing wide media attention after local police posted his story on their Facebook page, calling him a “hero” after his long journey by train and on foot from Zaporizhzhie in southeast Ukraine. “I got my hope from my mom wanting me to go,” Hassan said in an interview before appearing as a guest at a pro-Ukraine demonstration i…