Updates Beam Fn API container used by Dataflow at HEAD (#37088)

Author: chamikaramj

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

@@ -35,6 +35,6 @@
 # Update this tag whenever there is a change that
 # requires changes to SDK harness container or SDK harness launcher.
 
-BEAM_DEV_SDK_CONTAINER_TAG = 'beam-master-20251205'
+BEAM_DEV_SDK_CONTAINER_TAG = 'beam-master-20251210'
 
 DATAFLOW_CONTAINER_IMAGE_REPOSITORY = 'gcr.io/cloud-dataflow/v1beta3'