Allow correct retrieval of circuit with initialize instruction from qpy file

[SoranaAurelia]

Summary

This PR fixes #11158 . It adds the necessary conditions and cases for treating the StatePreparation instruction when reading from a qpy file.

Details and comments

When loading a circuit that had an initialize instruction (with an index or a label as parameter) from a qpy file, a QiskitError was thrown because these cases were not treated when the circuit was rebuilt, more specifically in the read instruction function.

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Pull Request Test Coverage Report for Build 6909812262

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• 7 of 7 (100.0%) changed or added relevant lines in 1 file are covered.
• 3 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.02%) to 85.898%

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Files with Coverage Reduction	New Missed Lines	%
crates/qasm2/src/lex.rs	3	91.67%

Totals
Change from base Build 6892258856:	0.02%
Covered Lines:	65945
Relevant Lines:	76771

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💛 - Coveralls

[SoranaAurelia]

Maybe a bit out of the scope of this ticket, but I saw that this piece of code of 5 lines (or equivalent code

qiskit/test/python/circuit/test_circuit_load_from_qpy.py

Lines 485 to 490 in daeceef

	qpy_file = io.BytesIO()
	dump(qc, qpy_file)
	qpy_file.seek(0)
	new_circ = load(qpy_file)[0]
	self.assertEqual(qc, new_circ)
	self.assertDeprecatedBitProperties(qc, new_circ)

) is repeated throughout this file a lot of times. Wouldn't it be better if we had in this test file a similar function as the one in qpy/test_circuit_load_from_qpy ?

qiskit/test/python/qpy/test_circuit_load_from_qpy.py

Lines 34 to 42 in af643eb

	def assert_roundtrip_equal(self, circuit):
	"""QPY roundtrip equal test."""
	qpy_file = io.BytesIO()
	dump(circuit, qpy_file)
	qpy_file.seek(0)
	new_circuit = load(qpy_file)[0]
	self.assertEqual(circuit, new_circuit)
	self.assertEqual(circuit.layout, new_circuit.layout)

[jakelishman]

Yeah, we could potentially improve this. This particular file is older that test/qpy/test_circuit_load_from_qpy.py, and to be honest, I don't know why this one still exists - I thought it had been moved into the test/python/qpy one some time ago. You're right that it would be better in a follow-up PR. If you'd like to make such a PR, it would be welcome.

[SoranaAurelia]

I would like to make a PR with the refactoring of this file. I will open an issue and associated PR shortly! Thanks

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[jakelishman]

Thank you for this! Please could you add a "bugfix" release note briefly explaining the change?

[jakelishman]

Yeah, we could potentially improve this. This particular file is older that test/qpy/test_circuit_load_from_qpy.py, and to be honest, I don't know why this one still exists - I thought it had been moved into the test/python/qpy one some time ago. You're right that it would be better in a follow-up PR. If you'd like to make such a PR, it would be welcome.

[jakelishman]

Thanks!