com.google.protobuf.util.Timestamps deprecations refer to unavailable JavaTimeConversions type

[SanjayVas]

What version of protobuf and what language are you using?
Version: 4.27.4 via com.google.protobuf:protobuf-java-util Maven artifact
Language: Kotlin JVM

What operating system (Linux, Windows, ...) and version?
Linux (Debian Bookworm)

What runtime / compiler are you using (e.g., python version or gcc version)
Kotlin 2 + JDK 17

What did you do?
Steps to reproduce the behavior:

1. Write code that references com.google.protobuf.util.Timestamps.add
2. Observe deprecation warning
3. Attempt to follow documented instructions for deprecation
4. Compilation error as referenced type is not available

What did you expect to see
Either

1. The referenced JavaTimeConversions type is available
2. No deprecation warning

What did you see instead?
A deprecation warning referencing an unavailable type.

Anything else we should know about your project / environment
There are some MOE comments that make it seem like the deprecation annotation and documentation were supposed to be stripped from the open source release.