[chore] [forwardconnector] use defined struct for config #15362

Job	Run time
govulncheck	47s
setup-environment	16s
checks	1m 49s
cross-build-collector (darwin, amd64)	36s
lint	2m 52s
cross-build-collector (darwin, arm64)	56s
test-coverage	3m 20s
cross-build-collector (linux, 386)	1m 12s
cross-build-collector (linux, amd64)	40s
unittest-matrix (~1.21.3)	1m 53s
cross-build-collector (linux, arm64)	56s
unittest-matrix (~1.20.10)	1m 20s
cross-build-collector (linux, ppc64le)	1m 6s
cross-build-collector (linux, arm, 7)	57s
cross-build-collector (linux, s390x)	1m 21s
cross-build-collector (windows, 386)	1m 14s
cross-build-collector (windows, amd64)	1m 14s
unittest	1s
	22m 30s

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