[chore]: enable gofumpt linter for testbed (#36299) #15977

Job	Run time
arm-unittest-matrix (receiver-0)	5m 48s
arm-unittest-matrix (receiver-1)	7m 28s
arm-unittest-matrix (receiver-2)	8m 31s
arm-unittest-matrix (receiver-3)	7m 9s
arm-unittest-matrix (processor-0)	3m 51s
arm-unittest-matrix (processor-1)	4m 37s
arm-unittest-matrix (exporter-0)	3m 11s
arm-unittest-matrix (exporter-1)	9m 39s
arm-unittest-matrix (exporter-2)	4m 14s
arm-unittest-matrix (exporter-3)	5m 33s
arm-unittest-matrix (extension)	5m 22s
arm-unittest-matrix (connector)	4m 29s
arm-unittest-matrix (internal)	6m 3s
arm-unittest-matrix (pkg)	3m 40s
arm-unittest-matrix (cmd-0)	1m 8s
arm-unittest-matrix (cmd-1)	1m 51s
arm-unittest-matrix (other)	4m 19s
arm-unittest	1s
	1h 26m 54s

Provide feedback