Dorothy A. Brown will not seek re-election next year, putting a bow on her 20-year tenure as the clerk of the Cook County Circuit Court.Brown’s announcement via Politico Illinois comes a day before the Cook County Democratic Party begins slating candidates for countywide and statewide positions in the 2020 election.Four potential candidates will ask for the party’s backing — Cook County Board of Review Commissioner Michael M. Cabonargi; state Sen. Iris Y. Martinez, D-Chicago; Jacob J. Meister, the owner …