[python] Release GIL in VFS bindings

[nguyenv]

Issue and/or context:

Follow up to #3543

Changes:

Release GIL for long-lived I/O methods open, read, and seek.

[bkmartinjr]

construction of python objects requires the GIL - read() doesn't correctly protect this code

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.26%. Comparing base (1c8b1bd) to head (d725c32).
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3553      +/-   ##
==========================================
+ Coverage   86.21%   86.26%   +0.04%     
==========================================
  Files          55       55              
  Lines        6348     6348              
==========================================
+ Hits         5473     5476       +3     
+ Misses        875      872       -3     

Flag	Coverage Δ
python	86.26% <ø> (+0.04%)	⬆️

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Components	Coverage Δ
python_api	86.26% <ø> (+0.04%)	⬆️
libtiledbsoma	∅ <ø> (∅)