Originally, the step was I wait for 5 seconds. This has been modified to I wait until I see "File upload completed!" This means it keeps trying to find the text "File Upload Completed" until it timeouts.
This is PR is reliant on this being merged in: silverstripe-labs/silverstripe-behat-extension#27
Modfied Step I wait for 5 Seconds to be more robust
Fixes #944: More Robust wait for text