spec: fix flaky wiki-and-tiny spec
spec: fix flaky wiki-and-tiny spec

use <form element>.submit instead of clicking form button

Change-Id: Ic5fba22f8fdf603fafff705ea18094a4ac30fd16
Reviewed-on: https://gerrit.instructure.com/143424
Tested-by: Jenkins
Reviewed-by: Jeremy Putnam <b030d6d6f199f844ec424882be473c2ab9adc93b@instructure.com>
Product-Review: Robert Lamb <bf934bf7cdbebe5899399a138c0cb75c4d783999@instructure.com>
QA-Review: Robert Lamb <bf934bf7cdbebe5899399a138c0cb75c4d783999@instructure.com>

sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,sfu/canvas-lms