Set sdk_harness_container_images for Dataflow prime jobs

[damccorm]

Specifically at following locations.

 

beam/runners/google-cloud-dataflow-java/src/main/java/org/apache/beam/runners/dataflow/DataflowRunner.java

Line 1340 in 13d1d27

if (useUnifiedWorker(options)) {

 

beam/sdks/python/apache_beam/runners/dataflow/internal/apiclient.py

Line 282 in 13d1d27

if _use_unified_worker(options):

 

Imported from Jira BEAM-12980. Original Jira may contain additional context.
Reported by: chamikara.