pipelines fix(backend): add commonEnvs to driver for PVCs

Description of your changes:

This PR adds commonEnvs to the driver container. This will now expose the KFP_POD_NAME and KFP_POD_UID env vars. This PR then updatesInPodName to take advantage of KFP_POD_NAME to accurately get the full pod name without the 63 char truncation issue seen when using hostname (seen in issue #12350)

This supersedes #12351, which attempted to address this issue but was not properly tested. After deploying that change, it was discovered it did not work as expected, due to the ARGO_POD_NAME env var not being exposed in the main container. This PR contains the correct implementation and has been validated in a live cluster.

Testing Evidence:

Using the following pvc hello world file with a long pipeline name:

from kfp import dsl
from kfp import kubernetes
from kfp import compiler

@dsl.component
def producer() -> str:
    with open('/data/file.txt', 'w') as file:
        file.write('Hello world')
    with open('/data/file.txt', 'r') as file:
        content = file.read()
    print(content)
    return content

@dsl.component
def consumer() -> str:
    with open('/data/file.txt', 'r') as file:
        content = file.read()
    print(content)
    return content


@dsl.pipeline
def my_pipeline_test_super_long_name_to_check_for_any_possible_errors_maybe():
    pvc1 = kubernetes.CreatePVC(
        # can also use pvc_name instead of pvc_name_suffix to use a pre-existing PVC
        pvc_name_suffix='-my-pvc',
        access_modes=['ReadWriteMany'],
        size='5Gi',
        storage_class_name='standard',
    )

    # write to the PVC
    task1 = producer()
    kubernetes.mount_pvc(
        task1,
        pvc_name=pvc1.outputs['name'],
        mount_path='/data',
    )

    # read to the PVC
    task2 = consumer()
    kubernetes.mount_pvc(
        task2,
        pvc_name=pvc1.outputs['name'],
        mount_path='/data',
    )
    task2.after(task1)

    delete_pvc1 = kubernetes.DeletePVC(
        pvc_name=pvc1.outputs['name']
    ).after(task2)

# Compile the pipeline
if __name__ == "__main__":
    compiler.Compiler().compile(pipeline_func=my_pipeline_test_super_long_name_to_check_for_any_possible_errors_maybe, package_path="kubeflow_pipeline.yaml")

KFP_POD_NAME exposed in main container Screenshot 2025-11-30 at 10 11 44 PM