Add simple loading and default state to datasourcewrapper (#1815)

platform/ui/src/components/EmptyStudies/EmptyStudies.js

@@ -3,12 +3,13 @@ import PropTypes from 'prop-types';
 import classnames from 'classnames';
 import { Icon, Typography } from '@ohif/ui';
 
-const EmptyStudies = ({ className }) => {
+// TODO: Add loading spinner to OHIF + use it here.
+const EmptyStudies = ({ className, isLoading }) => {
   return (
     <div className={classnames('flex-col inline-flex items-center', className)}>
       <Icon name="magnifier" className="mb-4" />
       <Typography className="text-primary-light" variant="h5">
-        No studies available
+        {!isLoading ? 'No studies available' : 'Loading...'}
       </Typography>
     </div>
   );