Support explicit dependencies with scala_artifact

[alonsodomin]

In #19128 we added support for a scala_artifact target implemented as a target generator that would emit jvm_artifact targets based on the Scala version for their resolve field.

This solution works fine with dependency inference as the target generator will be ignored by the AllJvmArtifactTargets implementation. However it introduces a bug when the end user decides to provide an explicit dependency between a scala_source target and a scala_artifact one.

This PR prevents scala_artifacts to be matched by the JvmArtifactFieldSet and provides with an implementation of ClasspathEntryRequest that helps resolve the transitive dependency that exists between the target generator and the actual jvm_artifact target.

[ci skip-build-wheels]
[ci skip-rust]

[Eric-Arellano]

Thanks!