add test case with labels as nil #8473

Job	Run time
build-container / Building containerized agent	8m 29s
harvest-test-linux / Linux harvest tests (ubuntu-20.04)	1m 7s
harvest-test-macos / MacOS harvest tests (macos-13)	1m 49s
linter-linux / Run Linter	1m 29s
harvest-test-macos / MacOS harvest tests (macos-14)	43s
linter-linux / Validate code	54s
linter-macos / Lint tests	2m 26s
linter-windows / Lint tests	6m 9s
unit-test-linux / Unit tests for databind	39s
unit-test-linux / Unit tests	4m 38s
unit-test-macos / unit tests	4m 35s
unit-test-windows / Windows unit tests	6m 54s
proxy-tests-linux / Proxy tests	2m 11s
test-build / Test binary compilation for all (linux) platforms:arch	7m 3s
unit-test-linux / Coveralls finish	2s
	49m 8s

Provide feedback