Closes: #44994
The problem with failing KubernetesJobOperator when using the parallelism option starts to appear from version 8.4.1, according to #44994.

Reason: As KubernetesJobOperator inherits from KubernetesPodOperator, it also uses some of the parent methods.
One of these, get_or_create_pod, is set to find only one or no pod during execution. In case the method finds two pods, it raises the exception 'More than one pod found'. While this is appropriate for the KubernetesPodOperator logic, KubernetesJobOperator could use more than one pod during execution.
That's why in this PR a new method, get_pods, was added. It will be more suitable for the logic of this operator. Also, a new attribute, self.pods, has been introduced in the operator. This attribute is needed for handling the logic of the do_xcom_push and get_logs flags.
Change KubernetesJobTrigger to handle KubernetesJobOperator with parallelism and deferrable flag.
Change GKEStartJobOperator.execute_deferrable to handle multiple pods.
Change GKEJobTrigger to handle multiple pods.
Adjust system test example_kubernetes_engine_job.py in google provider to reflect changes.
Adjust and add unit tests in providers: cncf/kubernetes, google

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