[processor/filter] Remove old config style from readme #28499

Job	Run time
collector-build	5m 9s
docker-build	5m 17s
supervisor-test	55s
kubernetes-test-matrix (v1.26.0, receiver/k8sclusterreceiver)	4m 43s
kubernetes-test-matrix (v1.26.0, processor/k8sattributesprocessor)	4m 54s
kubernetes-test-matrix (v1.26.0, receiver/kubeletstatsreceiver)	4m 13s
kubernetes-test-matrix (v1.26.0, receiver/k8sobjectsreceiver)	3m 13s
kubernetes-test-matrix (v1.25.3, receiver/k8sclusterreceiver)	4m 59s
kubernetes-test-matrix (v1.25.3, processor/k8sattributesprocessor)	4m 38s
kubernetes-test-matrix (v1.25.3, receiver/kubeletstatsreceiver)	4m 18s
kubernetes-test-matrix (v1.25.3, receiver/k8sobjectsreceiver)	3m 31s
kubernetes-test-matrix (v1.24.7, receiver/k8sclusterreceiver)	4m 52s
kubernetes-test-matrix (v1.24.7, processor/k8sattributesprocessor)	4m 34s
kubernetes-test-matrix (v1.24.7, receiver/kubeletstatsreceiver)	4m 28s
kubernetes-test-matrix (v1.24.7, receiver/k8sobjectsreceiver)	3m 22s
kubernetes-test-matrix (v1.23.13, receiver/k8sclusterreceiver)	4m 54s
kubernetes-test-matrix (v1.23.13, processor/k8sattributesprocessor)	4m 35s
kubernetes-test-matrix (v1.23.13, receiver/kubeletstatsreceiver)	4m 29s
kubernetes-test-matrix (v1.23.13, receiver/k8sobjectsreceiver)	3m 24s
kubernetes-test	1s
	1h 20m 29s

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