Adding an errorPlacement callback throws an error.

[alsoto25]

Describe the bug

After trying to customize the config for a field by adding a errorPlacement callback, we noticed that it's not behaving the way it should and in fact it's throwing an error before even being able to access the callback.

To Reproduce

Steps to reproduce the behavior:

1. Add a valid field to the config
2. Add an errorPlacement callback function to the field
3. See console error

Expected behavior

Config should correctly run the errorPlacement callback function.

Screenshots