LANSING, Mich. — The Michigan Democratic Party is challenging the petition signatures of three top Republican candidates for governor with one lawyer alleging “massive criminal forgery” took place within one campaign. Attorneys working on behalf of the Democrats turned in the challenges against former Detroit police Chief James Craig, conservative commentator and businesswoman Tudor Dixon and businessman Perry Johnson on Tuesday, before the 5 p.m. challenge deadline. Ten Republicans have filed to run for their party’s nomination in the Aug. 2 primary. Candidates for governor must submit 15,000…