Bug 1069380 - Use link role instead of button for open action in cards view

Changes the button role on the screenshotView to link, and adds the aria-hidden=true attribute to the iconButton to hide it from AT's. Added tests to ensure the aria properties in the cards view.
Merge pull request #24863 from jobara/1069380

Bug 1069380 - Use link role instead of button for open action in cards view