fix: incorrect formState after doc save (#9573)

### What?
When the document is saved the formState was not being reset from the
server.

### Why?
getFormState was not being called onSuccess of the form submission

### How?
The `Form` onSuccess function now allows for an optional return type of
`FormState` if the functions returns formState then we check to see if
that differs from the current formState on the client. If it does then
we dispatch the `REPLACE_STATE` action with the newState.

Fixes https://github.com/payloadcms/payload/issues/9423