grpc-observability was accidentally included in grpc-bom in 1.45 even
though it was not published to Maven Central. This is intended to reduce
the likelihood of such things reoccurring. We only include a project in
the bom if it is using maven-publish and if the publishing task is
enabled.
onlyIf is very similar to enabled, except it is processed just before
the task is run. We need a more static property here, so swap to
enabled. If a project uses onlyIf in the future, grpc-bom won't be able
to automatically exclude it.
protoc-gen-grpc-java isn't useful in a BOM because the Gradle plugin
doesn't support BOMs (google/protobuf-gradle-plugin#412) and it seems
unlikely the Maven plugin would as well.
Right now the type is pom, which is useless; nobody cares about the pom
itself. We'd need to use a type of exe and repeat it for each platform
(classifier). Given that it is a strange case and we can't actually test
the results and having it in the bom might lead a user to trying to make
it work, let's just remove it for now until it provides value.
Fixes#8936