fix PropType error in Calendar story (#5544)
fix PropType error in Calendar story (#5544)

Co-authored-by: britt6612 <e534fef94e183e6e88c1f0a20613d4061104039c@users.noreply.github.com>
grommet/grommet,grommet/grommet,HewlettPackard/grommet,grommet/grommet,HewlettPackard/grommet,HewlettPackard/grommet