Use param-shift too for test_gradient_unitary_to_rot_two_qubit_jax

[antalszava]

#1412 works now on master - as noted there, this PR adds param-shift as a tested diff_method.

From the issue:

I've just run into this in the development of #1552. Once it is resolved, it would be nice to update the test
test_gradient_unitary_to_rot_two_qubit_jax in the test_unitary_to_rot.py file to include parameter-shift in addition to backprop.

Closes #1412.

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[codecov]

Codecov Report

Merging #3183 (494421d) into master (b728eb8) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #3183   +/-   ##
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  Coverage   99.69%   99.69%           
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  Files         274      274           
  Lines       23922    23922           
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  Hits        23848    23848           
  Misses         74       74           

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[rmoyard]

Thanks @antalszava, great catch 💯