chore: Revert to upstream nifti-reader-js

[effigies]

@nellh I think your PRs all got merged? They do an annoying thing where they put compiled results in the source directory, so merging in master was a bit of a pain and I'm not sure I did it right.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.73%. Comparing base (2311270) to head (1de61a2).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #296   +/-   ##
=======================================
  Coverage   87.73%   87.73%           
=======================================
  Files          65       65           
  Lines        4843     4843           
  Branches      789      789           
=======================================
  Hits         4249     4249           
  Misses        502      502           
  Partials       92       92           

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