feat : Add iOS lockscreen search widget

[Ytemiloluwa]

Phabricator:

https://phabricator.wikimedia.org/T352836

Notes

This PR is a follow up of #5321

Test Steps

1. Long press the lockscreen to add a new lockscreen widget.
2. Click on the blue customise button and click on the Lockscreen
3. Click on the Add widget Box, scroll down and click the Wikipedia button.
4. Tap or drag any of the .accessoryCircular or .accessoryRectangular widget to add it to the lockscreen.
5. Click the Done button to add the selected widget to Lockscreen.

Screenshots/Videos