test_ObjectiveFunction tolerance too stringent

[KrisThielemans]

FAILED src/xSTIR/pSTIR/tests/test_ObjectiveFunction.py::TestSTIRObjectiveFunction::test_gradient_inplace - AssertionError: 
Not equal to tolerance rtol=1e-07, atol=1e-05

Mismatched elements: 1 / 24025 (0.00416%)
Max absolute difference among violations: 0.00024414
Max relative difference among violations: 1.1090098e-07
 ACTUAL: array([[[0., 0., 0., ..., 0., 0., 0.],
        [0., 0., 0., ..., 0., 0., 0.],
        [0., 0., 0., ..., 0., 0., 0.],...
 DESIRED: array([[[0., 0., 0., ..., 0., 0., 0.],
        [0., 0., 0., ..., 0., 0., 0.],
        [0., 0., 0., ..., 0., 0., 0.],...
FAILED src/xSTIR/pSTIR/tests/test_ObjectiveFunction.py::TestSTIRObjectiveFunction::test_gradient_out - AssertionError: 
Not equal to tolerance rtol=1e-07, atol=1e-05

Mismatched elements: 1 / 24025 (0.00416%)
Max absolute difference among violations: 0.00024414
Max relative difference among violations: 1.1090098e-07
 ACTUAL: array([[[0., 0., 0., ..., 0., 0., 0.],
        [0., 0., 0., ..., 0., 0., 0.],
        [0., 0., 0., ..., 0., 0., 0.],...
 DESIRED: array([[[0., 0., 0., ..., 0., 0., 0.],
        [0., 0., 0., ..., 0., 0., 0.],
        [0., 0., 0., ..., 0., 0., 0.],...