chore: rm unused object

[maelle]

No description provided.

[github-actions]

This is how benchmark results would change (along with a 95% confidence interval in relative change) if 6351312 is merged into main:

• ✔️as_adjacency_matrix: 791ms -> 795ms [-1.7%, +2.82%]
• ✔️as_biadjacency_matrix: 770ms -> 767ms [-2.56%, +1.85%]
• ✔️as_data_frame_both: 1.53ms -> 1.53ms [-3.52%, +3.65%]
• ✔️as_long_data_frame: 4.05ms -> 4ms [-3.77%, +1.15%]
• ✔️es_attr_filter: 2.76ms -> 2.77ms [-2.36%, +2.77%]
• ✔️graph_from_adjacency_matrix: 122ms -> 121ms [-2.95%, +0.85%]
• ✔️graph_from_data_frame: 3.41ms -> 3.55ms [-4.17%, +12.21%]
• ✔️vs_attr_filter: 1.58ms -> 1.6ms [-5.63%, +7.22%]
• ✔️vs_by_name: 1ms -> 1.02ms [-1.59%, +5.26%]
  Further explanation regarding interpretation and methodology can be found in the documentation.