[serve] Add telemetry for users with Pydantic version < 2

[landscapepainter]

Why are these changes needed?

We need to keep on track of the users using pydantic version < 2 so we can make complete migration to use >= 2 after confirming there aren't any.

[edoakes]

@landscapepainter can we expand this to all ray applications, not just serve? We might be able to simplify things for ray in general by not handling pydantic <2.0.

You can still get the same info that you have here by filtering to library usage of serve + pydantic < 2.0

[zcin]

Suggested change

	SERVE_PYDANTIC_V2_UNUSED = 33;
	SERVE_PYDANTIC_V1_USED = 33;

[github-actions]

This pull request has been automatically marked as stale because it has not had
any activity for 14 days. It will be closed in another 14 days if no further activity occurs.
Thank you for your contributions.

You can always ask for help on our discussion forum or Ray's public slack channel.

If you'd like to keep this open, just leave any comment, and the stale label will be removed.

[github-actions]

This pull request has been automatically closed because there has been no more activity in the 14 days
since being marked stale.

Please feel free to reopen or open a new pull request if you'd still like this to be addressed.

Again, you can always ask for help on our discussion forum or Ray's public slack channel.

Thanks again for your contribution!