Fix deprecation of iterable `CircuitInstruction` under Qiskit 1.2 (backport #636)

[mergify[bot]]

This fixes the following warnings that currently are triggered in the development version tests:

test/cutting/test_wire_cutting_transforms.py: 88 warnings
test/cutting/test_cutting_workflows.py: 4 warnings
  /home/runner/work/circuit-knitting-toolbox/circuit-knitting-toolbox/circuit_knitting/cutting/wire_cutting_transforms.py:79: DeprecationWarning: Treating CircuitInstruction as an iterable is deprecated legacy behavior since Qiskit 1.2, and will be removed in Qiskit 2.0. Instead, use the `operation`, `qubits` and `clbits` named attributes.
    other=instructions[0],

test/utils/test_transforms.py: 76 warnings
  /home/runner/work/circuit-knitting-toolbox/circuit-knitting-toolbox/test/utils/test_transforms.py:40: DeprecationWarning: Treating CircuitInstruction as an iterable is deprecated legacy behavior since Qiskit 1.2, and will be removed in Qiskit 2.0. Instead, use the `operation`, `qubits` and `clbits` named attributes.
    if len(gate[1]) == 2:
```<hr>This is an automatic backport of pull request #636 done by [Mergify](https://mergify.com).

[coveralls]

Pull Request Test Coverage Report for Build 9875848172

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 9847454472:	0.0%
Covered Lines:	3496
Relevant Lines:	3662

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💛 - Coveralls