* Allow MediaPickerScreen users to select the media selection mode (single or multiple)
* Fix cancellation
* Add support for multiple media URLs on the MediaUploadPreviewScreen.
* Support processing more URLs on the `MediaUploadingPreprocessor` and sending more on the `MediaUploadPreviewScreen`
* Add feature flag for `multipleAttachmentUploadEnabled`
* Add a label showing the current preview item index in the MediaUploadPreviewScreen
* Add support for dragging and dropping or pasting multiple items at the same time.
* Support sharing more than one file through the share extension.
* Limit the number of items that can be shared in one go to 5.
* Fix unit tests
* Fix incorrect fatal error when dealing with single selection media pickers.
* Document the `multipleAttachmentUploadEnabled` usage in the context of the MediaPicker.
* Use a task group for processing selected media in the photo library picker.
* Use a task group for processing multiple selected media in the MediaUploadingPreprocessor
* Switch the maximum number of items that can be shared to 10.
* Allow multiple items to be pasted at the same time.
This patch implements support for sending locations within threads by following a similar behavior to the other screens: pass the thread root between the various state machine states until the action is finally invoked.
This patch add the `threadRootEventID` as a parameter to media sending functions and forwards the timeline thread root between various application states to the place where its needed.
The 2 missing items are Locations and Polls which currently don't have any support on the Rust side for being sent within threads. That will come in a separate PR.
