fix: 🐛 Fix ghost shadow on thumb (#1113)

* fix: 🐛 Fix ghost shadow on thumb

Updated react-dnd package for the lates. Refactored thumbnail component

Closes: 1087

* feat: 🎸 Code review

Set flex instead of float. Add cypress tag to thumb container

* feat: 🎸 Code review. Revised style when no description

platform/ui/src/components/index.js

@@ -1,4 +1,4 @@
-import { StudyBrowser, ThumbnailEntry } from './studyBrowser';
+import { StudyBrowser, Thumbnail } from './studyBrowser';
 import { LayoutButton, LayoutChooser } from './layoutButton';
 import { MeasurementTable, MeasurementTableItem } from './measurementTable';
 import { Overlay, OverlayTrigger } from './overlayTrigger';
@@ -44,9 +44,9 @@ export {
   StudyList,
   TableList,
   TableListItem,
+  Thumbnail,
   TableSearchFilter,
   TablePagination,
-  ThumbnailEntry,
   ToolbarSection,
   Tooltip,
   AboutModal,