Gravity Perks - Preview Submission 1.3.20

Improved support for displaying a multi-file upload field's files while editing entries using GP Entry Blocks or GP Nested Forms.

Fixed PHP notice that could show if there are submitted File Upload fields without values.

Fixed conflict where Preview Submission was preventing merge tag drop downs for other plugins/perks such as GP Unique ID from showing fields on the current page.
Added "Update URI" to plugin header to improve security.