improve qti 2 detection

test plan:
* import the second package referenced in the ticket
(with "QTImgr" in the title)
* should import the questions correctly

refs #CNVS-14569

Change-Id: I5ab413fc6a843b47bc641713915117e757192858
Reviewed-on: https://gerrit.instructure.com/38800
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Bracken Mosbacker <bracken@instructure.com>
Product-Review: Bracken Mosbacker <bracken@instructure.com>
QA-Review: Clare Strong <clare@instructure.com>