Simplify typify of Generators in JAXLinker

[ricardoV94]

Minor code cleanup, generators don't have dtype

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📚 Documentation preview 📚: https://pytensor--1470.org.readthedocs.build/en/1470/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.03%. Comparing base (5f5be92) to head (49e4780).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1470      +/-   ##
==========================================
- Coverage   82.03%   82.03%   -0.01%     
==========================================
  Files         214      214              
  Lines       50398    50397       -1     
  Branches     8897     8897              
==========================================
- Hits        41345    41344       -1     
  Misses       6848     6848              
  Partials     2205     2205              

Files with missing lines	Coverage Δ
pytensor/link/jax/linker.py	96.15% <100.00%> (-0.08%)	⬇️

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