Add content description to QR code image for talkback.

- Rename string name for reuse purpose.

Test: Visual
Flag: EXEMPT bug fix
Bug: 350603175
Change-Id: Id5b1383c9cf1c2509a621bb9b225e0efeb58ca7f

src/com/android/settings/wifi/dpp/WifiDppQrCodeGeneratorFragment.java

@@ -114,6 +114,7 @@ public class WifiDppQrCodeGeneratorFragment extends WifiDppQrCodeBaseFragment {
         super.onViewCreated(view, savedInstanceState);
 
         mQrCodeView = view.findViewById(R.id.qrcode_view);
+        mQrCodeView.setContentDescription(getString(R.string.qr_code_content_description));
 
         final WifiNetworkConfig wifiNetworkConfig = getWifiNetworkConfigFromHostActivity();
         if (wifiNetworkConfig.isHotspot()) {