bigtable/beam test(s) are failing

[minherz]

Description

After the dependency upgrades in #9234 one or more tests under bigtable/beam/workload-generator fail in Java 11 (sponge) and Java 17 (sponge).

Based on the errors it looks like the failing test is bigtable.WorkloadGeneratorTest.testDeployedPipeline and it fails because the missing object gs://cloud-bigtable-dataflow-templates/generate-workload.json

Remove Ignore attribute from the tests after fixing the issue.