fix(frontend): make the panel usable with screen readers (#6907)

* fix(frontend): make the panel usable with screen readers

* fix(frontend): keep mobile tab names and the inbound expiry hint

Review of #6907 found two gaps in the screen-reader pass:

- On phone-width screens catTabLabel renders only the icon and names the
  tab by putting aria-label on it, but callers now pass that icon with
  aria-hidden for the desktop label, so every Settings, Xray and Host
  category tab lost its name under TalkBack. catTabLabel now clears
  aria-hidden on the icon it uses as the name.
- DateTimePicker forwarded id and aria-label but not aria-describedby,
  so the inbound expiry hint ("leave blank to never expire") was never
  attached. It now forwards it on both the Gregorian and Jalali input.

frontend/src/pages/index/ThroughputCard.tsx

@@ -47,12 +47,12 @@ export default function ThroughputCard({
         </div>
         <div className="ov-wide-legend">
           <div className="ov-legend-label">
-            <ArrowUpOutlined style={{ color: accent }} />
+            <ArrowUpOutlined aria-hidden style={{ color: accent }} />
             {t('pages.index.upload')}
             <span className="ov-legend-num">{SizeFormatter.speedFormat(status.netIO.up)}</span>
           </div>
           <div className="ov-legend-label">
-            <ArrowDownOutlined style={{ color: downColor }} />
+            <ArrowDownOutlined aria-hidden style={{ color: downColor }} />
             {t('pages.index.download')}
             <span className="ov-legend-num">{SizeFormatter.speedFormat(status.netIO.down)}</span>
           </div>