Lessen CEO Jay McKee and Fifth Wall managing partner Brendan Wallace (LinkedIn, Fifth Wall, iStock) A historic year for proptech fundraising has produced another unicorn. Lessen, a real estate management platform that connects property owners and operators to electricians, cleaners and other service providers, raised $170 million in a Series B round, pushing its total funding so far to $214 million — nearly quadruple its previous fundraising — and valuing the two-and-a-half year-old company at more than $1 billion. Proptech venture capital firm Fifth Wall, which led Lessen’s $35 million Series A round in June, returned to lead the new round. Khosla Ventures, General Catalyst and Navitas Capital were also…