With Chicago office vacancy rates at an all-time high and companies tentatively beginning to herd employees back into communal settings, co-working spaces — hard hit during the pandemic — are making a comeback. Two major co-working spaces opened this month in Chicago, including an expansive Fulton Market location from the once high-flying WeWork, and a new entry from Minnesota-based fitness chain Life Time, which launched a 39,000-square-foot space adjacent to its recently opened athletic club in River North. “Co-working is here to stay, and many of the entities that survived the pandemic are …