Pin scipy to <1.16 and temporary workaround (backport #964)

[mergify]

Summary

Pins the Scipy dependency to be < 1.16, as a workaround for the failures caused by Scipy 1.16 (#957). PR #961 is expected to resolve this compatibility issue and unpin Scipy to the latest stable version once again.

Suggestion for Qiskit Machine Learning users

As a workaround, please downgrade the Scipy library in your local virtual environments:

pip install scipy==1.15

If this fails, you may try to add the following flags

pip install --force-reinstall -v "scipy==1.15"

To restore Scipy's latest version, you can run pip install --upgrade scipy.

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This is an automatic backport of pull request #964 done by [Mergify](https://mergify.com).

[coveralls]

Pull Request Test Coverage Report for Build 16204796284

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 90.637%

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Totals
Change from base Build 15686647801:	0.0%
Covered Lines:	4366
Relevant Lines:	4817

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💛 - Coveralls