Keep badge out of natural tab order

If I've understood things correctly, this should allow regular
users to skip over the badge elements with Tab, while still
allowing screen reader apps to read/focus the badge elements.

https://github.com/ankitects/anki/pull/2721#issuecomment-1761740985
https://forums.ankiweb.net/t/anki-23-10-beta-5/35677/18

ts/components/Badge.svelte

@@ -31,6 +31,7 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
     on:click
     on:mouseenter
     on:mouseleave
+    tabindex="-1"
 >
     <IconConstrain {iconSize} {widthMultiplier} {flipX}>
         <slot />