fix when empty string is given for value for calendar (#5875)
fix when empty string is given for value for calendar (#5875)

Co-authored-by: Brittany Archibeque <4c43263c0f6ac4977dfd4587be05cb6c714b7fc8@Brittanys-MacBook-Pro-2.local>
Co-authored-by: Eric Soderberg <7357255ec89aa29cb38b14d4ed1295aca420bf0b@hpe.com>
grommet/grommet,grommet/grommet,grommet/grommet