cirq-google - get CZ gate noise properties from engine calibration da…

…ta (#7116)

* cirq-google - get CZ gate noise properties from QVM calibration data

This adds 3 new CZ-gate calibration metrics to be translated from
`cirq_google.Calibration` to `cirq_google.GoogleNoiseProperties`

- two_qubit_parallel_cz_gate_xeb_pauli_error_per_cycle (gate_pauli_errors)
- two_qubit_parallel_cz_gate_xeb_entangler_theta_error_per_cycle (fsim_errors)
- two_qubit_parallel_cz_gate_xeb_entangler_phi_error_per_cycle (fsim_errors)

* The key needs to be a type not an instance

cirq-google/cirq_google/engine/calibration_to_noise_properties.py

@@ -54,10 +54,12 @@
 }
 GATE_PREFIX_PAIRS: Dict[Type['cirq.Gate'], str] = {
     cg_ops.SycamoreGate: 'two_qubit_parallel_sycamore_gate',
+    ops.CZPowGate: 'two_qubit_parallel_cz_gate',
     ops.ISwapPowGate: 'two_qubit_parallel_sqrt_iswap_gate',
 }
 GATE_ZPHASE_CODE_PAIRS: Dict[Type['cirq.Gate'], str] = {
     cg_ops.SycamoreGate: 'syc',
+    ops.CZPowGate: 'cz',
     ops.ISwapPowGate: 'sqrt_iswap',
 }