[Refactor] Fixing mypy issues of `syft/` #5076

Job	Run time
pr-tests-syft-notebook-container (ubuntu-latest, 3.9, single_container, api/0.8)	14m 28s
pr-tests-syft-notebook-container (ubuntu-latest, 3.10, single_container, api/0.8)	14m 17s
pr-tests-syft-notebook-container (ubuntu-latest, 3.11, single_container, api/0.8)	13m 40s
pr-tests-syft-notebook-python (ubuntu-latest, 3.11, python, tutorials)	8m 56s
pr-tests-syft-notebook-python (macos-latest, 3.11, python, tutorials)	10m 36s
pr-tests-syft-notebook-python (3.9, ubuntu-latest, python, tutorials)	9m 23s
pr-tests-syft-notebook-python (3.10, ubuntu-latest, python, tutorials)	8m 33s
pr-tests-syft-security (ubuntu-latest, 3.11)	1m 58s
pr-tests-syft-unit (ubuntu-latest, 3.11)	6m 5s
pr-tests-syft-unit (macos-latest, 3.11)	18m 33s
pr-tests-syft-unit (windows-latest, 3.11)	18m 49s
pr-tests-syft-unit (3.9, ubuntu-latest)	19m 12s
pr-tests-syft-unit (3.10, ubuntu-latest)	6m 51s
	2h 31m 21s

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