test_str and test_mul for TestStructureGraph of analysis.graphs are failing

[DanielYang59]

After fixing assert_str_content_equal implementations in #4205, noticed the following tests for TestStructureGraph of analysis.graphs are failing.

Note: to recreate the following failures, you have to pull the assert_str_content_equal fix from #4205.

cc @mkhorton

pytest tests/analysis/test_graphs.py::TestStructureGraph::test_str

E           AssertionError: Strings are not equal (whitespaces ignored):
E           ===================== Actual =====================
E           Structure Graph
E           Structure: 
E           Full Formula (H1)
E           Reduced Formula: H2
E           abc   :   5.000000   5.000000  50.000000
E           angles:  90.000000  90.000000  90.000000
E           pbc   :       True       True       True
E           Sites (1)
E             #  SP      a    b    c
E           ---  ----  ---  ---  ---
E             0  H       0    0    0
E           Graph: bonds
E           from    to  to_image    
E           ----  ----  ------------
E              0     0  (1, 0, 0)   
E              0     0  (0, 1, 0)   
E           
E           ==================== Expected ====================
E           Structure Graph
E           Structure:
E           Full Formula (H1)
E           Reduced Formula: H2
E           abc   :   5.000000   5.000000  50.000000
E           angles:  90.000000  90.000000  90.000000
E           Sites (1)
E             #  SP      a    b    c
E           ---  ----  ---  ---  ---
E             0  H       0    0    0
E           Graph: bonds
E           from    to  to_image
E           ----  ----  ------------
E              0     0  (1, 0, 0)
E              0     0  (-1, 0, 0)
E              0     0  (0, 1, 0)
E              0     0  (0, -1, 0)

pytest tests/analysis/test_graphs.py::TestStructureGraph::test_mul

E           AssertionError: Strings are not equal (whitespaces ignored):
E           ===================== Actual =====================
E             1  H     0.5    0   -0
E           Graph: bonds
E           from    to  to_image    
E           ----  ----  ------------
E              0     0  (0, 1, 0)   
E              0     1  (0, 0, 0)   
E              0     1  (-1, 0, 0)  
E              1     1  (0, 1, 0)   
E           ==================== Expected ====================
E           Graph: bonds
E           from    to  to_image
E           ----  ----  ------------
E              0     0  (0, 1, 0)
E              0     0  (0, -1, 0)
E              0     1  (0, 0, 0)
E              0     1  (-1, 0, 0)
E              1     1  (0, 1, 0)
E              1     1  (0, -1, 0)