[VizBuilder] Implement cancel, save, save and return button flow on TopNav

[abbyhu2000]

Subtask of #960

When creating a new wizard from dashboard, the topnav should have:

1. cancel should discard the current changes and go back to dashboard
2. save button should show save modal

When editing an existing wizard from dashboard, the topnav should have:

1. cancel button should discard the current changes
2. save as button should show save modal
3. save and return should save all the changes to the existing wizard and return to dashboard

[ashwin-pc]

@btzeng In the case of Save and Return, does the "Add to Dashboard after saving" toggle still make sense?

[abbyhu2000]

@btzeng In the case of Save and Return, does the "Add to Dashboard after saving" toggle still make sense?

i think it does make sense since it provides an option for user to create a new visualization/wizard(cuz user can turn save as new visualization toggle on) and then save this new one to the dashboard? @ashwin-pc Save and Return only save the changes to the old wizard, it doesn't create a new one.

[ahopp]

@btzeng In the case of Save and Return, does the "Add to Dashboard after saving" toggle still make sense?

Echoing @abbyhu2000 on this one, I also think it makes sense. Provide another option to safe with new, IMO. And it doesn't seem to decrement the user flow in any meaningful way.

[joshuarrrr]

@abbyhu2000 Is this done and ready to be closed? It looks like the parent issue is closed and complete.

[ashwin-pc]

@joshuarrrr I think we want to keep this issue open since we have a draft PR open to add the cancel flow. That PR is still in draft because we realized that we were implementing sketchy UX patterns to enable these save and cancel flows. @KrooshalUX is working on a better save workflow that we can use across the app.

@KrooshalUX do we have a tracking issue for that?