Test of execute_w_pt fails intermittently

[Misty-W]

Issue Description

Test of execute_w_pt fails intermittently.

def test_execute_with_pauli_twirling():
       num_qubits = 3
       num_layers = 20
       circuit, _ = generate_mirror_circuit(
           nlayers=num_layers,
           two_qubit_gate_prob=1.0,
           connectivity_graph=nx.complete_graph(num_qubits),
       )
       expval = execute_with_pauli_twirling(
           circuit, amp_damp_executor, num_circuits=10
       )
      assert 0 <= expval < 0.4

E assert 0.4206504255533218 < 0.4

How to Reproduce

Examples observed in CI:
https://github.com/unitaryfund/mitiq/actions/runs/5135406857/jobs/9240786361
https://github.com/unitaryfund/mitiq/actions/runs/5130264396/jobs/9228821628
https://github.com/unitaryfund/mitiq/actions/runs/5125269561/jobs/9218229039?pr=1845
https://github.com/unitaryfund/mitiq/actions/runs/5115832329/jobs/9197434600
https://github.com/unitaryfund/mitiq/actions/runs/5061296432/jobs/9085321787

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