Show folders scanned instead of files scanned

ui/src/layout/ActivityPanel.js

@@ -127,7 +127,7 @@ const ActivityPanel = () => {
                 {translate('activity.totalScanned')}:
               </Box>
               <Box component="span" flex={1}>
-                {scanStatus.count}
+                {scanStatus.folderCount || '-'}
               </Box>
             </Box>
           </CardContent>

ui/src/reducers/activityReducer.js

@@ -1,6 +1,8 @@
 import { EVENT_SCAN_STATUS, EVENT_SERVER_START } from '../actions'
 
-const defaultState = { scanStatus: { scanning: false, count: 0 } }
+const defaultState = {
+  scanStatus: { scanning: false, folderCount: 0, count: 0 },
+}
 
 export const activityReducer = (
   previousState = {