Add marshaler to prometheus receiver config #918

Job	Run time
collector-build	5m 13s
docker-build	7m 31s
supervisor-test	1m 14s
kubernetes-test-matrix (v1.30.0, receiver/k8sclusterreceiver)	4m 40s
kubernetes-test-matrix (v1.30.0, processor/k8sattributesprocessor)	5m 38s
kubernetes-test-matrix (v1.30.0, receiver/kubeletstatsreceiver)	4m 35s
kubernetes-test-matrix (v1.30.0, receiver/k8sobjectsreceiver)	3m 32s
kubernetes-test-matrix (v1.23.17, receiver/k8sclusterreceiver)	4m 43s
kubernetes-test-matrix (v1.23.17, processor/k8sattributesprocessor)	6m 7s
kubernetes-test-matrix (v1.23.17, receiver/kubeletstatsreceiver)	4m 19s
kubernetes-test-matrix (v1.23.17, receiver/k8sobjectsreceiver)	3m 17s
kubernetes-test	1s
	50m 50s

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