Make project's relationship with Qiskit consistent in the copyright headers (backport #646)

[mergify]

Most CKT copyright headers say "This code is a Qiskit project." ... but a few stragglers say "This code is part of Qiskit." This PR updates those stragglers.

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This is an automatic backport of pull request #646 done by Mergify.

[github-actions]

Pull Request Test Coverage Report for Build 10478540512

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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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 95.467%

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Totals
Change from base Build 10475644256:	0.0%
Covered Lines:	3496
Relevant Lines:	3662

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💛 - Coveralls