[Valid] [Validator] [Constraints] [DEPRECATION] Added deprication note on Valid constraint validator for deep option.

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | yes
| Tests pass?   | yes
| Fixed tickets | #12695 
| License       | MIT
| Doc PR        | -
I would have said: "The "deep" option for the Valid constraint ..."