Use button semantics and styles for link elements that work as buttons

[JasonYeMSFT]

Standard to meet:

• Elements that trigger "in-application actions" should be <button> elements. Accessibility Insights should register the element as a "button".

• Elements that "open link in external browsers" should be <a> elements, with a blue underline. Accessibility Insights should register the element as a "link".

• Action buttons of the renderer window notification (customized actions and the default close action)

[MRayermannMSFT]

In 1.34, please fill out the "Elements needing updating:" list and then we can determine how we want to triage/distribute the actual doing of this work.

[JasonYeMSFT]

Investigation is done for 1.34.0.