Ensure all custom field validations are using default field validations

[rchlfryn]

Describe the bug
When working on the pages collection, I noticed a user can now create a page without any blocks in the layout field. This is because we added a custom validation that by default will use what we write in place of the default. Payload has a great solution for this: Reusing default field validations

We should double check all custom field validations to ensure they are reusing default field validations