Because SecureBootConfigDxe use FileExplorerLib now, but
FileExplorerLib is not in the dsc file of the package
that use SecureBootConfigDxe. Now add it to pass build.
Cc: David Wei <david.wei@intel.com>
Cc: Tim He <tim.he@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: David Wei <david.wei@intel.com>
