ci(pipelines): enable ci label injection for all tiflow pull jobs (#4298)## WhatEnable CI annotation injection for all `pingcap/tiflow` pull pipelinesby switching Kubernetes agent pod spec loading from:- `yamlFile POD_TEMPLATE_FILE`to:- `yaml pod_label.withCiLabels(POD_TEMPLATE_FILE, REFS)`This change is applied to all tiflow pull pipeline scripts under:- `pipelines/pingcap/tiflow/**/pull_*.groovy` (commit: c85044a)