FileUploadPreview is the default UI component for rendering a preview of attached file within MessageInput component.
file type attachments currently attached to message, which is being composed in
state: 'uploaded'; // or 'finished'
Removes attached file in message, which is being composed in
MessageInput component. By default, this function is attached to
onPress handler for close button in FileUploadPreview.
It takes index of file (to be removed) in
fileUploads array as parameter.
This function is used internally by
uploadNewFile function, and is used for purpose retry mechanism.