KANSAS CITY, Mo. — The Kansas City Royals’ best pitcher in May fell back with a thud as a losing streak continued through early June. Brady Singer was shelled for seven runs in five innings — that included three home runs allowed — as the Houston Astros blasted their way to a 10-3 victory over KC on Friday night at Kauffman Stadium. This was only the latest in a Royals season that continues to circle the drain. KC lost its fifth game in a row and now has dropped 12 of 14. The team’s 16-34 record also remains as the worst in baseball. Singer — the Royals’ best story during a 9-20 May — had allo…