Steps to reproduce:

1. Clean installation of IBEXA DXP 3.3
2. Create a new content type with image and do not check the "can be a thumbnail" option
3. Generate migration file using command line:

   php bin/console ibexa:migrations:generate --type=content_type --mode=update
   

4. In migration yaml file, in the fields of our content type with image add

   thumbnail: true

Result:
The thumbnail option is not taken into account

Expected Result:
The thumbnail option should be considered