Feature Value Validation Settings

### Is your feature request related to a problem? Please describe.

We want to be able to give control of changing features and values over to external teams that may or may not have knowledge of the exact format a feature value needs to be in to work correctly. While some of this can be accomplished through change management what we would like to have is at a feature level some way of validating that the value, either as a variant, the default, or a segment/identity override matches certain conditions like matching a regex or being valid yaml/json.

### Describe the solution you'd like.

Some setting on a feature that would allow us to input a regex field that is used to validate any feature value input and will not update if it does not pass. I would also like to have some setting that requires the value to be valid yaml/json if possible.

### Describe alternatives you've considered

Manual review with change requests can cover some of this ground but having automation that allow us to be more confident in reviewing the changes is always nice.

### Additional context

_No response_