longer sleep for screenshot test

Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

app/src/androidTest/java/com/owncloud/android/ui/activity/UploadFilesActivityIT.kt

@@ -70,7 +70,7 @@ class UploadFilesActivityIT : AbstractIT() {
         }
 
         waitForIdleSync()
-        shortSleep()
+        longSleep()
 
         screenshot(sut.fileListFragment.binding.emptyList.emptyListView)
     }