Sub-community field is under Additional Metadata, needs to be moved to required

[astrochun]

Email notifications by data reviewers is/will be configured for PPPL for a select number of sub-communities. Because this field is additional, submitters are less likely to select from the list. As such, no notification would be triggered to the data reviewers. If this can be moved to the required field or if the UI ensures that the submitter goes through each metadata tab.