Backport of "qtitem: don't potentially leak a large number of buffers" into 1.18
requested to merge tpm/gst-plugins-good:backport-mr-1004-into-1.18-qtitem-destruction-release-stored-buffers into 1.18
Backport of !1004 (merged) "qtitem: don't potentially leak a large number of buffers".
Commits:
- fbf60a61 qtitem: don't potentially leak a large number of buffers