QA: Update keepgoing test to reflect default state of editor

By default the editor is wikitext. As a result the KeepGoing test
is failing as it expects VisualEditor to be the default. Update it
so that it switches to VisualEditor and passes again.

Change-Id: I5d1b40223699d0a0bc64ccd34173660b5b0dae82
Merge "QA: Update keepgoing test to reflect default state of editor"