chore: rm modifs of variable not used in logic branch

[maelle]

No description provided.

[github-actions]

This is how benchmark results would change (along with a 95% confidence interval in relative change) if 7289e95 is merged into main:

• ✔️as_adjacency_matrix: 786ms -> 785ms [-1.05%, +0.62%]
• ✔️as_biadjacency_matrix: 783ms -> 781ms [-2.59%, +2.02%]
• ✔️as_data_frame_both: 1.51ms -> 1.5ms [-1.38%, +0.29%]
• ✔️as_long_data_frame: 3.91ms -> 3.91ms [-0.85%, +0.85%]
• ✔️es_attr_filter: 3.12ms -> 3.22ms [-1.03%, +7.6%]
• ✔️graph_from_adjacency_matrix: 135ms -> 135ms [-0.51%, +0.52%]
• ✔️graph_from_data_frame: 3.4ms -> 3.4ms [-0.85%, +0.75%]
• ✔️vs_attr_filter: 1.74ms -> 1.68ms [-6.97%, +1.12%]
• ✔️vs_by_name: 1.18ms -> 1.16ms [-4.94%, +1.24%]
  Further explanation regarding interpretation and methodology can be found in the documentation.