fix: make wrong-mode pushforward/pullback return the correct array type

[gdalle]

With this PR, the iteration over basis vectors still runs on the CPU, which means that the same prep can be reused without race conditions. Conversion is performed at the end to port the data back to the GPU.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.19%. Comparing base (2b7c5e9) to head (ce5819e).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #974      +/-   ##
==========================================
+ Coverage   94.11%   98.19%   +4.08%     
==========================================
  Files         135      135              
  Lines        7980     7999      +19     
==========================================
+ Hits         7510     7855     +345     
+ Misses        470      144     -326     

Flag	Coverage Δ
DI	98.96% <100.00%> (+5.67%)	⬆️
DIT	96.22% <ø> (ø)

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