Type hints for existing installation tests

[asnare]

This PR implements add type hints for existing unit tests, resolving warnings during project linting. The warnings were during mypy processing, because we had type hints within the test body but the test function itself had none:

tests/unit/test_installation.py:459: note: By default the bodies of untyped functions are not checked, consider using --check-untype
d-defs  [annotation-unchecked]                                                                                                      
tests/unit/test_installation.py:471: note: By default the bodies of untyped functions are not checked, consider using --check-untype
d-defs  [annotation-unchecked]                                                                                                      
tests/unit/test_installation.py:483: note: By default the bodies of untyped functions are not checked, consider using --check-untype
d-defs  [annotation-unchecked]                                    
tests/unit/test_installation.py:495: note: By default the bodies of untyped functions are not checked, consider using --check-untype
d-defs  [annotation-unchecked]                                    
tests/unit/test_installation.py:507: note: By default the bodies of untyped functions are not checked, consider using --check-untype
d-defs  [annotation-unchecked]                                                                                                      
tests/unit/test_installation.py:519: note: By default the bodies of untyped functions are not checked, consider using --check-untype
d-defs  [annotation-unchecked]                                    
tests/unit/test_installation.py:531: note: By default the bodies of untyped functions are not checked, consider using --check-untype
d-defs  [annotation-unchecked]                                                                                                      
tests/unit/test_installation.py:543: note: By default the bodies of untyped functions are not checked, consider using --check-untype
d-defs  [annotation-unchecked]                                    

(All resolved.)

[github-actions]

✅ 40/40 passed, 2 skipped, 2m7s total

_{Running from acceptance #263}

[sundarshankar89]

LGTM