ConstraintEdit form should load config without overrides

Thanks for the issue and patch. Tagging for testing.

Assigning to myself for testing since this looks pretty simple to test.

I was able to reproduce the problem following the given steps.
The MR applies cleanly and the database stored value is used as default (in the "character_length" field for example).

This is working as intended and since the password policy entity is only used to retrieve and update the constraint, it looks safe to merge.