Feature Request: Restrict File Upload to only one item

[ArakTaiRoth]

Info

Requested by Fahad Mahmood (https://goa-dio.slack.com/archives/C02PLLT9HQ9/p1708023926796239)

The team naturally wants to restrict the number of files a user can upload. They do this already by ignoring any files uploaded after the first one. But the file selector window that gets opened, still allows you to select multiple files. Is there a way to restrict the number of files allowed during upload.

Acceptance Criteria:

1. Property for the FileUploadInput that removes the multiple property from the input - so that only single files are allowed. Users will still be expected to write their own validation for drag and drop.
2. If a user selects multiple files for drag and drop, only the first file (in alphabetical order) will be uploaded.

[ArakTaiRoth]

@Spark450 Talk to the designer to figure out how they would actually like to see this implemented