[BC] Collections with references to entities in __toString() are broken.

[KDederichs]

Describe the bug
When you have an entity in a collection field with a __toString() function that accesses an entity, you'll get an error.

I think that was introduces by 3f979b6 since now if you add entities it'll always add the same Name for the collection entry as well, prompting me to believe it'll generate the name once when rendering the template and using that as default name then.

I think the easiest solution here would be to just not try to render the name of the collection item when it's being added.

To Reproduce
Edit a Crud page with a collection of items that access an associated (or other) non initiated entity.

(OPTIONAL) Additional context
Error:

It rendering the same name multiple times when adding entities without a __toString() function (first one was already there)

[Seb33300]

I think this is a duplicate of #7627

[KDederichs]

It is, but you closed it without a fix (except go through and look for all the toString methods that might cause the issue).
It's still a BC break though and doesn't make sense that a newly created collection item has a title, especially if it's generated by a prototype which is always the same.