LocalSimulator happily and incorrectly accepts result types on Sum observables

[kshyatt-aws]

Describe the bug

>>> from braket.circuits import Circuit, Observable
>>> circ = Circuit().h(0).rx(1, 0.5).cnot(0, 1).ry(0, 0.5).expectation(Observable.X() @ Observable.X()+Observable.Z() @ Observable.Z(), target=[[0,1],[0,1]])  
>>> circ.result_types
[Expectation(observable=Sum(TensorProduct(X('qubit_count': 1), X('qubit_count': 1)), TensorProduct(Z('qubit_count': 1), Z('qubit_count': 1))), target=[QubitSet([Qubit(0), Qubit(1)]), QubitSet([Qubit(0), Qubit(1)])])] # Expectation of Sum observable
>>>
>>> from braket.devices import LocalSimulator
>>> device = LocalSimulator()
>>>
>>> task = device.run(circ, shots=0)
>>> task2 = device.run(circ, shots=10)
>>> task.result()
GateModelQuantumTaskResult(task_metadata=TaskMetadata(braketSchemaHeader=BraketSchemaHeader(name='braket.task_result.task_metadata', version='1'), id='f24c3c54-0826-49e3-95be-b78769af2879', shots=0, deviceId='braket_sv', deviceParameters=None, createdAt=None, endedAt=None, status=None, failureReason=None), additional_metadata=AdditionalMetadata(action=Program(braketSchemaHeader=BraketSchemaHeader(name='braket.ir.openqasm.program', version='1'), source='OPENQASM 3.0;\nqubit[2] q;\nh q[0];\nrx(0.5) q[1];\ncnot q[0], q[1];\nry(0.5) q[0];\n#pragma braket result expectation x(q[0]) @ x(q[1]) + z(q[0]) @ z(q[1])', inputs={}), dwaveMetadata=None, ionqMetadata=None, rigettiMetadata=None, oqcMetadata=None, xanaduMetadata=None, queraMetadata=None, simulatorMetadata=None, iqmMetadata=None), result_types=[ResultTypeValue(type=Expectation(observable=['x', 'x'], targets=[0, 1], type=<Type.expectation: 'expectation'>), value=0.8775825618903722)], values=[0.8775825618903722], measurements=None, measured_qubits=None, measurement_counts=None, measurement_probabilities=None, measurements_copied_from_device=None, measurement_counts_copied_from_device=None, measurement_probabilities_copied_from_device=None, _result_types_indices={"{'observable': ['x', 'x'], 'targets': [0, 1], 'type': <Type.expectation: 'expectation'>}": 0})
>>> task2.result()
GateModelQuantumTaskResult(task_metadata=TaskMetadata(braketSchemaHeader=BraketSchemaHeader(name='braket.task_result.task_metadata', version='1'), id='86fafa7e-1d50-499e-bd37-20c6bf40f1b7', shots=10, deviceId='braket_sv', deviceParameters=None, createdAt=None, endedAt=None, status=None, failureReason=None), additional_metadata=AdditionalMetadata(action=Program(braketSchemaHeader=BraketSchemaHeader(name='braket.ir.openqasm.program', version='1'), source='OPENQASM 3.0;\nqubit[2] q;\nh q[0];\nrx(0.5) q[1];\ncnot q[0], q[1];\nry(0.5) q[0];\n#pragma braket result expectation x(q[0]) @ x(q[1]) + z(q[0]) @ z(q[1])', inputs={}), dwaveMetadata=None, ionqMetadata=None, rigettiMetadata=None, oqcMetadata=None, xanaduMetadata=None, queraMetadata=None, simulatorMetadata=None, iqmMetadata=None), result_types=[ResultTypeValue(type=Expectation(observable=['x', 'x'], targets=[0, 1], type=<Type.expectation: 'expectation'>), value=0.8)], values=[0.8], measurements=array([[1, 1],
       [0, 0],
       [0, 0],
       [1, 1],
       [1, 1],
       [1, 1],
       [0, 0],
       [1, 1],
       [1, 0],
       [1, 1]]), measured_qubits=[0, 1], measurement_counts=Counter({'11': 6, '00': 3, '10': 1}), measurement_probabilities={'11': 0.6, '00': 0.3, '10': 0.1}, measurements_copied_from_device=True, measurement_counts_copied_from_device=False, measurement_probabilities_copied_from_device=False, _result_types_indices={"{'observable': ['x', 'x'], 'targets': [0, 1], 'type': <Type.expectation: 'expectation'>}": 0})

To reproduce A clear, step-by-step set of instructions to reproduce the bug.

Expected behavior The local simulator should reject any expectation, variance, or sample of a Sum observable from the BDK. What it definitely should not do is only calculate the expectation value of the first term and return that.

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System information A description of your system. Please provide:

• Amazon Braket Python SDK version:
• Amazon Braket Python Schemas version:
• Amazon Braket Python Default Simulator version:
• Python version:

Additional context Add any other context about the problem here.

[speller26]

Looks like a problem with the the OpenQASM interpreter; we'll have to generate a new parser that recognizes sum observables.