It’s her prerogative. On Monday, an explosive trailer was released for an upcoming TV special that will investigate Britney Spears’ life just 1½ years after her conservatorship was lifted. The special, titled “TMZ Investigates: Britney Spears: The Price of Freedom,” reportedly will give viewers an inside look into the 41-year-old pop star’s marriage to Sam Ashgari, a failed intervention, her …