Mackenzie Shirilla was shooting for the stars from behind bars ... because in an undated jail call, she says she wants Kim Kardashian to be her lawyer. The call -- obtained by PEOPLE and recorded while Mackenzie was held at the Cuyahoga County Corrections Center in Ohio -- features the now-21-year-old discussing the growing media attention surrounding her case. Speaking to an unidentified person, Mackenzie wonders if Kim K may have seen the coverage ... before admitting, "I'm real nervous and I