When the customer tries to move the video to the first position of the product
image. at that time, the error would be generated.

step to reproduce:
-Install the website_sale
-open Invoicing > vendors > Products > open any Product
-open sales Notepage
-click on add a Media
-past any video url > save it
-click on Go To website from the state button
-click on Edit button > again double click on the image
-then click on a right side position of re-order

error- Key Error:'video_url'

After applying our commit, if the customer got a validation error when
the customer attempted to swap the video into the product images at
 the first position. There is a controller named
`/shop/product/resequence-image` which called, when the customer
changes the position of the video.

https://github.com/odoo/odoo/blob/3ce90ddf33f59a80de34cbafd05679d0817d0076/addons/website_sale/controllers/main.py#L582-L587



The `image res_model` will then receive the `product.image` model when a
customer moves a video from the third to the second position, and that model
locates the field known as `video_url`. However, when a customer moves a
video from the second to the first position, `image res_model` will then
receive the `product.product`  model, and that model finds the same field but
does not have that field in it.

sentry-4393257638

closes odoo/odoo#132471

Signed-off-by: Antoine Vandevenne (anv) <anv@odoo.com>