fix qiskit_device to support Aer v2 conventions

[timmysilv]

Tests suddenly began to fail with the release of Aer 0.13.0 yesterday. The main change is that it got upgraded to a V2 backend. The consequence is that we depended on the device name to check its behaviours.

Some code to highlight the change:
Qiskit-Aer v0.12.2

>>> dev = qml.device("qiskit.aer", wires=2, backend="aer_simulator_unitary")
>>> dev.backend, dev.backend.options.method
(AerSimulator('aer_simulator_unitary'), 'unitary')

Qiskit-Aer v0.13.0

>>> dev = qml.device("qiskit.aer", wires=2, backend="aer_simulator_unitary")
>>> dev.backend, dev.backend.options.method
(AerSimulator('aer_simulator'), 'unitary')

We often check things like if some_method in dev.backend_name, so I had to update those checks to be more general and support the new (and undocumented!) V2 backend naming convention used with Aer.

Test change: for some reason, transpilation of the circuit in that one test turned a PauliZ into an RZ(-pi), and we were only applying the noise to Z gates. I just added RZ to the list of gates we apply noise on to fix it.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (6010d88) 100.00% compared to head (e0a6264) 100.00%.

Additional details and impacted files

@@            Coverage Diff            @@
##            master      #343   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files            7         7           
  Lines          309       320   +11     
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+ Hits           309       320   +11     

Files	Coverage Δ
pennylane_qiskit/qiskit_device.py	100.00% <100.00%> (ø)

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[mudit2812]

Thanks for the quick fix!