fix: allow zero values for disk provisioned IOPS and throughput in Dataflow worker options

Author: bambadiouf1

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

@@ -203,9 +203,9 @@ def __init__(
       pool.diskSizeGb = self.worker_options.disk_size_gb
     if self.worker_options.disk_type:
       pool.diskType = self.worker_options.disk_type
-    if self.worker_options.disk_provisioned_iops:
+    if self.worker_options.disk_provisioned_iops is not None:
       pool.diskProvisionedIops = self.worker_options.disk_provisioned_iops
-    if self.worker_options.disk_provisioned_throughput_mibps:
+    if self.worker_options.disk_provisioned_throughput_mibps is not None:
       pool.diskProvisionedThroughputMibps = (
           self.worker_options.disk_provisioned_throughput_mibps)
     if self.worker_options.zone: