Skip japicmp for new modules

[rnorth]

Unblocks #4303

Have tested on #4303's branch; ./gradlew japicmp (across the entire codebase) works as it should.

e.g. for an unpublished module that has no available baseline:

> Task :azure:japicmp SKIPPED
Skipping task ':azure:japicmp' as task onlyIf is false.
:azure:japicmp (Thread[Execution worker for ':' Thread 3,5,main]) completed. Took 0.0 secs.

and for a published module:

> Task :trino:japicmp
Deleting stale output file: /Users/rnorth/github.com/testcontainers/testcontainers-java/modules/trino/build/reports/japi.html
Build cache key for task ':trino:japicmp' is e6e0b417a3a36294106bc367c2fff84f
Task ':trino:japicmp' is not up-to-date because:
  No history is available.
Stored cache entry for task ':trino:japicmp' with cache key e6e0b417a3a36294106bc367c2fff84f
:trino:japicmp (Thread[Execution worker for ':' Thread 3,5,main]) completed. Took 0.252 secs.