LANSING, Mich. — Michigan Democrats accused the state Republican Party on Thursday of crossing an ethical line in a volatile political climate by including the personal cellphone numbers of Democratic candidates in campaign mailers. State House Democrats said at least six of their candidates were featured in recent GOP attack pieces that told recipients to contact them by calling numbers that were their cellphone numbers. Jaime Churches of Wyandotte, a Democrat and a teacher running in the 27th House District, said she found out about the mailer featuring her number because one of her students…