Changing the type of a data source can break formulas (import fails)

If you create a list data source then change it's type to get row existing formulas can break.

To reproduce:

• Create a list data source
• Use it in a table element (creating current_record formulas)
• Use it in other elements (with a row index in it)
• Now change the type:
  • The frontend should already show a first crach
  • Then if you reload and try to publish(duplicate, snapshot, ...) the application the backend fails hard while importing the "list" formulas as "get" formulas for both types of formules.

To solve that we should:

• Fix the frontend to allow this operation without failing
• When the application is published, we should emptied the formula or just not migrate it. If we keep it we should just check it doesn't break elsewhere.

Ideally, later, it will be part of the "Check before publish modal" that summarize what is going wrong in the application but that's another ticket.

Related to sentry issue BASEROW-SAAS-BACKEND-2S3