Accessibility: Button does not follow the established design pattern

[jason-me]

Issue

The "Sign In" button on the landing page does not follow the established design pattern for button controls. It is not focusable or actionable by the keyboard and does not announce a button role.

Expected Behavior

• WCAG 2.2 AA 4.1.2 Name, Role, Value requires that the button role is used.
• WCAG 2.2 A 2.1.1 Keyboard requires that interactive controls are focusable and operable with the keyboard.
• Screen reader and keyboard only users expect to be able to navigate to the control and that the proper accessible name and button role are announced when interacting with it.

Acceptance Criteria

• Make this control render as an HTML button or add role="button" and tabindex="0"
• Test with a screen reader JAWS, VoiceOver, NVDA, Orca, Talkback, etc.
• Ensure the control announces the accessible name which matches the visible label for the control and the button role

Linked to tracking issue: #456

[jason-me]

PR in pending review status for completion of this issue: #1054