Fix power() in subclass test for QuantumCircuit change (backport #172)

[mergify[bot]]

Summary

Qiskit tests against main have been failing lint recently due to power() in QuantumCircuit gaining an extra parameter. With 1.1 going live shortly, where it will become the stable version tested against here, this amends the test to work and pass lint for existing versions of Qiskit e.g 0.46 and 1.0 as well as 1.1

Details and comments

As it's just a test case fix there is no reno needed. I marked this for backporting to stable as it will affect any builds done there once 1.1 releases.

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This is an automatic backport of pull request #172 done by Mergify.

[coveralls]

Pull Request Test Coverage Report for Build 8965115888

Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 90.653%

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Totals
Change from base Build 8635185179:	0.0%
Covered Lines:	6488
Relevant Lines:	7157

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💛 - Coveralls