Richard Gonzmart, the fourth-generation owner of the iconic Columbia Restaurant chain based in Tampa, says it’s time for politicians to start listening on immigration. When federal immigration authorities arrived at his Sand Key restaurant in Clearwater in 2021 to find outdated and noncompliant work documents for 19 of his employees, he was forced to fire them all — including seven people who had worked with his family for decades. “With 2,000 employees, it becomes very difficult to monitor it,’’ Gonzmart said in an interview.