VE-1564 Use options API call to set whether user viewed dialog

https://wikia-inc.atlassian.net/browse/VE-1564
I know it is not introduced directly in this PR but could be cleaned up in it :) - Is there a reason for using two different names ("showVisualEditorTransitionDialog" and "showVETransitionDialog") for more or less the same thing? If not then let's change it.