Allow nubbin to change position when popover flips

[george-norris-salesforce]

Fixes #1211.

Allows the nubbin to change position when a popover flips

Before

After:

Pull Request Review checklist (do not remove)

• Review the appropriate Storybook stories. Open http://localhost:9001/.
• Review tests are passing in the browser. Open http://localhost:8001/.
• Review markup conforms to SLDS by looking at snapshot strings.
• Add year-first date and commit SHA to last-slds-markup-review in package.json and push.
• Request a review of the deployed Heroku app by the Salesforce UX Accessibility Team.
• Add year-first review date, and commit SHA, last-accessibility-review, to package.json and push.
• While the contributor's branch is checked out, run npm run local-update within locally cloned site repo to confirm the site will function correctly at the next release.

[interactivellama]

Ah sweet! Tell me when you want me to look at it. Looks like some lint issues are present.

[interactivellama]

@george-norris-salesforce I've added you as a collaborator. Please see email invite. That should give you rights to assign pull requests to me when you want to.

[interactivellama]

I went ahead and took a peak, cause I'm so excited. The non-orthogonal directions aren't showing arrows.

Should look like:

[george-norris-salesforce]

@interactivellama Just got back from PTO, taking a look now..

[stale]

This issue has been automatically marked as stale, because it has not had recent activity. It will be closed if no further activity occurs. Maintainers are responsible for tech debt and project health. This is most likely a new components or component feature request. Please submit a pull request for or request feedback on this feature. Thank you.

[salesforce-cla]

Thanks for the contribution! It looks like @george-norris-salesforce is an internal user so signing the CLA is not required. However, we need to confirm this.

[interactivellama]

Closing. @vintik has worked this into #1404.