Keyboard focus indicator is not visible on action.http button

Question

Reaching out from the Viva Pulse product - which uses Outlook's action.http buttons on some of the email notifications. Following a11y issue was filed against our team

Pre-Requisite:

1. Go to this designer, which pins the version to 1.0. https://amdesigner.azurewebsites.net/
2. Paste the JSON
3. Click Send to send yourself an email of the adaptive card
4. Open it on your mobile device on the Outlook app to test it.

Repro Steps:

1. Open the outlook application.
2. Press Tab key and navigate to the 'Extend by 3 days' and 'Copy Survey Link' button and observe the issue.

Actual Result:
While navigating on the 'Extend by 3 days', 'Copy survey link' button using tab key,ctrl+ tab key, alt+tab key., here keyboard focus indicator on 'buttons' are not visible.

Expected Results:
Keyboard focus indicator should be visible for the 'Extend by 3 days', 'Copy survey link' buttons when user navigates with keyboard.

More details:

Details of the issue can be found here: https://github.com/microsoft/AdaptiveCards-Mobile/issues/3