style(xftp): remove unused Int64 import from STM store

Author: shumvgolove

src/Simplex/FileTransfer/Server/Store/STM.hs

@@ -14,7 +14,6 @@ where
 
 import Control.Concurrent.STM
 import Control.Monad
-import Data.Int (Int64)
 import qualified Data.Map.Strict as M
 import qualified Data.Set as S
 import Simplex.FileTransfer.Protocol (FileInfo (..), SFileParty (..))