Relying on an exception to the general rule that “no quasi-contractual claim can arise when a contract exists between the parties concerning the same subject matter on which the quasi-contractual claim rests,” Industrial Lift v. Mitsubishi, 104 Ill.App.3d 357 (1982), Great American Insurance Co. sued a policyholder — Mallers Building LLC, owner of the century-old terra cotta clad high rise at Madison and Wabash in Chicago — for restitution of $4.9 million Great American paid to mitigate Mallers’ losses from a 2018 fire …