Wrong handling of images received from e.g.: WhatsApp

Steps to reproduce

1. Make sure to receive an image from any app that removes EXIF metadata, for example WhatsApp.
2. Try to import the photo from iCloud to NextCloud.
3. NextCloud will show the current datetime as date of the photo, while it should be the date the photo was originally received.

Expected behaviour

I expect NextCloud to take the datetime of when the photo was added to iCloud and set that datetime as 'Created On' EXIF metadata in case no 'Created On' EXIF metadata is present.
This will make sure the 'Created On' date will not be lost after export / import.

Actual behaviour

NextCloud does not set the 'Created On' metadata in case it is missing. Because of this it will show the current datetime as the 'Created On' datetime... leads to unexpected behaviour.

Screenshots

If applicable, add a screenshot showing the issue.

Logs

If applicable, you can post the iOS app or server logs (removing any sensitive information).

Reasoning or why should it be changed/implemented?

Right now, once you export any image that doesn't contain exif metadata (which are basically images received from any social media app), you will forever lose the datetime of receiving said image.
So let's say you export and then import the image back into iCloud i would expect the same order of photo's, and that's not the case right now.
By simply putting 'Created On' metadata in case it is not present, this issue is solved.

Environment data

iOS version: iOS 15.2

Nextcloud iOS app version: 4.1.0.17

Server operating system: Ubuntu 20.04

Web server: Apache

Database: MariaDB

PHP version: 8

Nextcloud version: 23.0.0

Start by tracing the iCloud import path and the iOS app's EXIF metadata handling. Check how images without a Created On value are dated, then verify that using the iCloud receipt date preserves ordering after export and re-import.