Fix type of basis_gates in BasicSimulator configuration (#13385)

`basis_gates` was getting set to `Target.operation_names`, which is a
`dict_keys` instance (maybe that should be changed to a more basic
type?), while typically `basis_gates` is a list. `dict_keys` instances
can not be deep copied, so code that usually deep copies a backend's
configuration could not work. Deep copying the configuration can happen
for example when using the `BasicSimulator` with sampler class like
`qiskit_ibm_runtime.SamplerV2` that puts the backend into its options
and then tries to deep copy the options.

qiskit/providers/basic_provider/basic_simulator.py

@@ -257,7 +257,7 @@ def configuration(self) -> BackendConfiguration:
                 backend_name=self.name,
                 backend_version=self.backend_version,
                 n_qubits=self.num_qubits,
-                basis_gates=self.target.operation_names,
+                basis_gates=list(self.target.operation_names),
                 gates=gates,
                 local=True,
                 simulator=True,

releasenotes/notes/basicsimulator-config-copy-5ecdfdf161e488f2.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    For :class:`~.BasicSimulator`, the ``basis_gates`` entry in the
+    configuration instance returned by the ``configuration()`` is now a list
+    rather than a ``dict_keys`` instance, matching the expected type and
+    allowing for configuration instance to be deep copied.