Fixed issue 3842 by comparison to an absolute error value

[JiahanBro]

Summary

Fixes #3842

Details and comments

The absolute value of the difference between the input to the value 1 has to be compared to the error bound given by _EPS in order to fulfill the if condition.

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[1ucian0]

Hi @JiahanBro!

Sorry for the delay here! The code was moved to qiskit/extensions/quantum_initializer/diagonal.py. Since it might be related with or affects #4375, maybe @ewinston can have a look to it?

[1ucian0]

Also, considering adding a test that fails in master and passes here. Thanks and my apologies again! Your contribution is valued :)

[ewinston]

@JiahanBro Don't worry about creating a test since I think it already exists in #4375 which will probably merge shortly after.

[ewinston]

@JiahanBro Can you resolve the conflict? The class has moved to "diagonal.py".

[JiahanBro]

Should I just close the pull request and delete the branch?

[ewinston]

Should I just close the pull request and delete the branch?

Whatever is convenient for you. It's a small change so maybe that's easier.