Fix(web): drag n drop shared link (#3030)

* add event to trigger uploadhandler

* add dragndrop store
to handle upload in album-viewer and individuel-shared-viewer
(only on shares)

* fix handleUploadAssets no parameter

* fix format

web/src/lib/stores/drag-and-drop-files.store.ts

@@ -0,0 +1,7 @@
+//store to track the state of the drag and drop and the files
+import { writable } from 'svelte/store';
+
+export const dragAndDropFilesStore = writable({
+	isDragging: false as boolean,
+	files: [] as File[]
+});