Drop torch_sparse dependency in datasets.* and io.*

[rusty1s]

No description provided.

[codecov]

Codecov Report

Merging #6132 (e463d5f) into master (901a255) will decrease coverage by 1.88%.
The diff coverage is 73.33%.

❗ Current head e463d5f differs from pull request most recent head 33777b6. Consider uploading reports for the commit 33777b6 to get more accurate results

@@            Coverage Diff             @@
##           master    #6132      +/-   ##
==========================================
- Coverage   86.25%   84.37%   -1.89%     
==========================================
  Files         363      363              
  Lines       20492    20481      -11     
==========================================
- Hits        17675    17280     -395     
- Misses       2817     3201     +384     

Impacted Files	Coverage Δ
torch_geometric/data/dataset.py	91.61% <0.00%> (ø)
torch_geometric/io/sdf.py	33.33% <33.33%> (+1.33%)	⬆️
torch_geometric/io/planetoid.py	75.32% <83.33%> (-2.99%)	⬇️
torch_geometric/io/tu.py	90.80% <100.00%> (-2.22%)	⬇️
torch_geometric/utils/loop.py	84.78% <100.00%> (ø)
torch_geometric/nn/models/dimenet_utils.py	0.00% <0.00%> (-75.52%)	⬇️
torch_geometric/nn/models/dimenet.py	14.90% <0.00%> (-52.76%)	⬇️
torch_geometric/profile/profile.py	36.27% <0.00%> (-26.48%)	⬇️
torch_geometric/nn/conv/utils/typing.py	81.25% <0.00%> (-17.50%)	⬇️
torch_geometric/nn/pool/asap.py	92.10% <0.00%> (-7.90%)	⬇️
... and 17 more

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