🔇 fix: Hide Button Icons from Screen Readers (#10776)

If you've got a screen reader that is reading out the whole page,
each icon button (i.e., `<button><SVG></button>`) will have both
the button's aria-label read out as well as the title from the
SVG (which is usually just "image").

Since we are pretty good about setting aria-labels, we should instead
use `aria-hidden="true"` on these images, since they are not useful
to be read out.

I don't consider this a comprehensive review of all icons in the app,
but I knocked out all the low hanging fruit in this commit.

client/src/components/Banners/Banner.tsx

@@ -41,7 +41,7 @@ export const Banner = ({ onHeightChange }: { onHeightChange?: (height: number) =
         className="h-8 w-8 opacity-80 hover:opacity-100"
         onClick={onClick}
       >
-        <XIcon className="mx-auto h-4 w-4" />
+        <XIcon className="mx-auto h-4 w-4" aria-hidden="true" />
       </button>
     </div>
   );