[Docs]: Process to upgrade to new Select Widget

[Nikhil-Nandagopal]

Need to add corrosponding doc related to the warning `stay up to date` for switch widget

[tzahari]

This would be helpful! Thank you

[jnikhila]

A generic how-to guide will be created as part of the ticket [Add doc/explainer video link to stay up-to-date alert for select widget] (#14462). Thus, closing this ticket.
CC: @dilippitchika / @pranavkanade