FakeService: filter: Fix field-existance check (#212) #626

Job	Run time
Build distribution packages	21s
Test with nox (amd64, ubuntu-24.04, 3.12, ci_checks_max)	1m 17s
Test with nox (amd64, ubuntu-24.04, 3.11, pytest_min)	43s
Test with nox (arm, ubuntu-24.04, 3.12, pytest_min)	52s
Test with nox (arm, ubuntu-24.04, 3.11, pytest_min)	51s
Test with nox (arm, ubuntu-24.04, 3.12, ci_checks_max)	1m 14s
Test with nox (arm, ubuntu-24.04, 3.11, ci_checks_max)	1m 17s
Test with nox (amd64, ubuntu-24.04, 3.11, ci_checks_max)	1m 7s
Test with nox (amd64, ubuntu-24.04, 3.12, pytest_min)	38s
Test documentation website generation	0s
Test package installation (arm, ubuntu-24.04, 3.12)	18s
Test package installation (amd64, ubuntu-24.04, 3.12)	19s
Test package installation (arm, ubuntu-24.04, 3.11)	25s
Test package installation (amd64, ubuntu-24.04, 3.11)	18s
Test package installation	2s
Test with nox	3s
Publish documentation website to GitHub pages	33s
Create GitHub release	0s
Publish packages to PyPI	0s
	10m 18s

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