Fix: properly filter custom feature/graph stores

[mananshah99]

The current method of filtering relied on the buggy str_to_edge_type, which would fail if a node type had __ in its name.

[codecov]

Codecov Report

Merging #5088 (7949386) into master (2a16256) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head 7949386 differs from pull request most recent head 7458051. Consider uploading reports for the commit 7458051 to get more accurate results

@@           Coverage Diff           @@
##           master    #5088   +/-   ##
=======================================
  Coverage   83.00%   83.00%           
=======================================
  Files         333      333           
  Lines       18368    18369    +1     
=======================================
+ Hits        15246    15247    +1     
  Misses       3122     3122           

Impacted Files	Coverage Δ
torch_geometric/loader/link_neighbor_loader.py	91.61% <100.00%> (ø)
torch_geometric/loader/neighbor_loader.py	94.93% <100.00%> (ø)
torch_geometric/loader/utils.py	81.57% <100.00%> (+0.16%)	⬆️

Help us with your feedback. Take ten seconds to tell us how you rate us.

[rusty1s]

LGTM. Thanks!