Posh nail salon Glosslab – whose investors include former Miss Universe Olivia Culpo, ex-Tinder CEO Sean Rad and The Chainsmokers — is closing stores and skipping rent at multiple locations as an aggressive expansion plan has run into trouble, The Post has learned.Last year, founder Rachel Glass — a former hedge-fund executive who started the chain in 2018, opening two salons in the Flatiron District and West Village — told Fox Business the company had raised “roughly $20 million” and opened 21 locations ac ...