Deprecate ExprSchema functions

[timsaucer]

Is your feature request related to a problem or challenge?

As a follow on to this comment:

#15646 (comment)

We can deprecate the functions like data_type, nullable, and metadata in ExprSchema after #15646 merges

Describe the solution you'd like

Deprecate with documentation of what the user should use next

Describe alternatives you've considered

Leave as is is also okay for these simple functions.

Additional context

No response

[ajita-asthana]

I want to work on this issue.

[ajita-asthana]

Would the since tag be part of a later version or the current one itself ?

[JSOD11]

Is this still being worked on? Happy to take a look if not.