Utilize HeteroData.set_value_dict in code base

[rusty1s]

No description provided.

[codecov]

Codecov Report

Merging #6974 (32e7a89) into master (81f2daa) will decrease coverage by 0.01%.
The diff coverage is 92.85%.

@@            Coverage Diff             @@
##           master    #6974      +/-   ##
==========================================
- Coverage   91.45%   91.45%   -0.01%     
==========================================
  Files         431      431              
  Lines       23453    23440      -13     
==========================================
- Hits        21449    21437      -12     
+ Misses       2004     2003       -1     

Impacted Files	Coverage Δ
torch_geometric/explain/explainer.py	89.02% <75.00%> (+0.78%)	⬆️
torch_geometric/data/hetero_data.py	90.88% <100.00%> (ø)
...ch_geometric/explain/algorithm/captum_explainer.py	98.66% <100.00%> (-0.07%)	⬇️
torch_geometric/loader/link_loader.py	95.55% <100.00%> (-0.15%)	⬇️
torch_geometric/loader/node_loader.py	95.71% <100.00%> (-0.18%)	⬇️

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more