Add a fullscreen button to TimelineMediaPreviewScreen and hook up swiping through the timeline. (#3638)

* Add a fullscreen button to media previews - Not ideal but the gestures conflict with the preview controller.

* Don't un-flip the preview thumbnail until the preview has disappeared, and only do it on iOS 18.

* Add all of the loaded items for previewing in the preview controller.

ElementX/Sources/Screens/FilePreviewScreen/View/TimelineMediaPreviewRedactConfirmationView.swift

@@ -138,8 +138,11 @@ struct TimelineMediaPreviewRedactConfirmationView_Previews: PreviewProvider, Tes
                                                         thumbnailInfo: .mockThumbnail,
                                                         contentType: contentType))
         
+        let timelineController = MockRoomTimelineController(timelineKind: .media(.mediaFilesScreen))
+        timelineController.timelineItems = [item]
         return TimelineMediaPreviewViewModel(context: .init(item: item,
-                                                            viewModel: TimelineViewModel.mock,
+                                                            viewModel: TimelineViewModel.mock(timelineKind: timelineController.timelineKind,
+                                                                                              timelineController: timelineController),
                                                             namespace: previewNamespace),
                                              mediaProvider: MediaProviderMock(configuration: .init()),
                                              photoLibraryManager: PhotoLibraryManagerMock(.init()),