The critics were somewhat half-hearted about the Huntington Theatre Company’s production of “A Confederacy of Dunces,’’ but the crowds were not. The show starring Nick Offerman of NBC’s “Parks and Recreation’’ became the highest-grossing show in the company’s 33-year history, earning more than $2.1 million during its 45-performance run that concluded Sunday. “A Confederacy of Dunces’’ overtook the sales record held by the Huntington’s 2013 production of “A Jungle Book.’’ The show, based on the Pulitzer Prize-winning novel by John Kennedy Toole, was adapted by Jeffrey Hatcher and directed by David Esbjornson. The production was presented in cooperation with a team of partners including Robert Guza, John Hardy, LSU Press, and Oscar-winning filmmaker Steven Soderbergh. In the show, Offerman played gaseous eccentric Ignatius J. Reilly, the Don Quixote of the French Quarter.