Fix a bug in isometry.rs (backport #12469)

[mergify]

Summary

After PR #12197 was merged, there is a bug with the following code:

num_qubits = 3
num_controls = 4
u = random_unitary(2 ** num_qubits)
ug = UnitaryGate(u)
cug = ug.control(num_controls)
cug 

The code is working for num_qubits = 1 or 2 but not for 3 or 4 or 5, and raises the following error:

/qiskit/circuit/library/generalized_gates/isometry.py:221, in Isometry._disentangle(self, circuit, q, diag, remaining_isometry, column_index, s)
    217 diagonal_mcg = self._append_mcg_up_to_diagonal(
    218     circuit, q, gate, control_labels, target_label
    219 )
    220 # apply the MCG to the remaining isometry
--> 221 v = isometry_rs.apply_multi_controlled_gate(v, control_labels, target_label, gate)
    222 # correct for the implementation "up to diagonal"
    223 diag_mcg_inverse = np.conj(diagonal_mcg).astype(complex, copy=False)

PanicException: assertion failed: j <= 1

Details and comments

The solution is to remove the assertion assert!(j <= 1) in crates/accelerate/src/isometry.rs:215:13

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This is an automatic backport of pull request #12469 done by [Mergify](https://mergify.com).

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[coveralls]

Pull Request Test Coverage Report for Build 9274742625

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 19 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.01%) to 89.619%

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Files with Coverage Reduction	New Missed Lines	%
crates/qasm2/src/lex.rs	7	92.37%
crates/qasm2/src/parse.rs	12	97.15%

Totals
Change from base Build 9164868799:	-0.01%
Covered Lines:	62247
Relevant Lines:	69457

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💛 - Coveralls