Revert device gradients fix

[puzzleshark]

[sc-19816]

[github-actions]

Hello. You may have forgotten to update the changelog!
Please edit doc/releases/changelog-dev.md with:

• A one-to-two sentence description of the change. You may include a small working example for new features.
• A link back to this PR.
• Your name (or GitHub username) in the contributors section.

[codecov]

Codecov Report

Merging #2595 (9fdbb72) into master (3fa7518) will increase coverage by 26.65%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           master    #2595       +/-   ##
===========================================
+ Coverage   72.92%   99.58%   +26.65%     
===========================================
  Files         245      245               
  Lines       19726    19724        -2     
===========================================
+ Hits        14386    19642     +5256     
+ Misses       5340       82     -5258     

Impacted Files	Coverage Δ
pennylane/interfaces/autograd.py	100.00% <ø> (ø)
pennylane/interfaces/execution.py	100.00% <0.00%> (+0.78%)	⬆️
pennylane/gradients/vjp.py	100.00% <0.00%> (+1.44%)	⬆️
...mplates/subroutines/fermionic_double_excitation.py	100.00% <0.00%> (+2.14%)	⬆️
pennylane/math/quantum.py	100.00% <0.00%> (+2.38%)	⬆️
pennylane/transforms/hamiltonian_expand.py	100.00% <0.00%> (+2.77%)	⬆️
pennylane/_grad.py	100.00% <0.00%> (+3.03%)	⬆️
pennylane/transforms/split_non_commuting.py	100.00% <0.00%> (+3.33%)	⬆️
pennylane/devices/default_qubit.py	100.00% <0.00%> (+3.48%)	⬆️
pennylane/transforms/batch_input.py	100.00% <0.00%> (+4.00%)	⬆️
... and 157 more

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[antalszava]

Thank you @puzzleshark! It would be great to add a test case to the test suite as per the suggested example from the relevant issue, such that we can be sure that the problem doesn't arise again.

Also, be sure to add a changelog item. 🙂

[antalszava]

Looks good 🎉