Accessibility: No speech in Ozone sidebar

Steps to reproduce:

• Enable accessibility support (either with --accessibility command line switch or via menus)
• Exit out into the main menu, and focus the ozone sidebar, IE by pressing backspace
• Navigate through the tabs

Expected: The currently focused sidebar item should be spoken, just like every other menu item.
Actual: There is absolutely no speech feedback while the sidebar is focused - not when the cursor enters it, and not while it moves through its items.

This is a pretty serious regression considering Ozone is now the default menu driver. I was helping a new user setup RetroArch for the first time and ran into this problem there. Needless to say it was extremely confusing because I didn't know how to switch away from the main menu to adjust settings and pressing right/left was not giving me the expected speech feedback.

Using Retroarch 1.8.5 on Windows. Mac and Linux are most likely also effected.

Start by reproducing the issue with accessibility support enabled, then trace the Ozone sidebar's focus and item-navigation handling. Compare it with other menu items that provide speech feedback. Done means the focused sidebar item is spoken both when entering the sidebar and while navigating through its tabs.