Missing artifact: Better handle job execution with artifact download tasks

If a job has artifact download task and the plan that is to produce the artifact never had a single successful build, the UI message is rather confusing, especially if there are multiple stages in the job. This can make a user think that Stage 1 has failed even though it's green: 

The only way to figure out what is going on is to check server logs:

Caused by: java.lang.IllegalArgumentException: Unable to find at least one successful result for plan: PROJ-ARTCaused by: java.lang.IllegalArgumentException: Unable to find at least one successful result for plan: PROJ-ART at com.atlassian.bamboo.plugins.artifact.ArtifactDownloaderRuntimeDataProvider.populateRuntimeTaskData(ArtifactDownloaderRuntimeDataProvider.java:110) at com.atlassian.bamboo.chains.ChainPluginSupportHelper.lambda$prepareRuntimeTaskData$0(ChainPluginSupportHelper.java:37)

There are 2 problems here:

1. Misleading message. It'd be great to actually display the reason for not adding the build to the queue, i.e. say that no artifacts are available while the job has artifact download task
2. The job is stuck in Waiting to be built state, even if there's an artifact available (successful build of the job that produces an artifact). Perhaps, it may make sense to fail the entire build and state the reason to do so.