Allow up to 5 images to be dragged and dropped in to one-on-one chats and in the timeline. Can be combined with the existing upload button. The upload file dialog has been changed to allow multiple selections. Drag and dropped images adhere to the following rules, with corresponding validations messages:
- Max 5 image
- Image size must be 0.5 MB or less
- File extension must be one of [".png", ".jpg", ".jpeg", ".heif", "tif", ".tiff"]
Drag and drop and uploaded images are now also deduplicated.
We were only resetting the `Image` source but not the consumer facing `imageSource`
property when removing a selected image from the image area.
This cause the `imageSource` to practically never change after an image has
been selected the first time. Selecting an image another time would open the
image area, but if the image happens to be the same as the first time, the `imageSource`
practically didn't change, causing the app to render an "empty" image.