transgui: fix crash at startup with file argument

pkgs/applications/networking/p2p/transgui/r988-compile-fix.patch

···
  function ParamStrUTF8(Param: Integer): utf8string;
  begin
 -  Result:=FileUtil.ParamStrUTF8(Param);
-+  Result:=ParamStrUTF8(Param);
++  Result:=LazUtf8.ParamStrUTF8(Param);
  end;
  
  function ParamCount: integer;