Update wagtailmedia/widgets.py
Update wagtailmedia/widgets.py

have version handling logic in one place

Co-authored-by: Dan Braghis <2591e5f46f28d303f9dc027d475a5c60d8dea17a@zerolab.org>
torchbox/wagtailmedia,torchbox/wagtailmedia,torchbox/wagtailmedia