Fluent upgrade Accessibility testing by devs (automated accessibility insights tool)

[ElinorW]

• Run accessibility insights tool
• Check narrator
• Keyboard navigation

Issues detected

• main header buttons missing aria-labels
• signed out icon missing alt text
• Resources version switch missing a label
• missing labels on edit collection check box
• missing tooltips on many icons e.g back arrow on collections, close button on dialogs, maximize/minimize sidebar
• keyboard focus on the tab headers is cut off/not clear