Update v2 sampler decoder (#1429)

* v2 sampler decoder

* reenable qctrl check

qiskit_ibm_runtime/sampler.py

@@ -90,10 +90,8 @@ def __init__(
         Sampler.__init__(self)
         BasePrimitiveV2.__init__(self, backend=backend, session=session, options=options)
 
-        raise NotImplementedError("SamplerV2 is not currently supported.")
-
-        # if self._service._channel_strategy == "q-ctrl":
-        #     raise NotImplementedError("SamplerV2 is not supported with q-ctrl channel strategy.")
+        if self._service._channel_strategy == "q-ctrl":
+            raise NotImplementedError("SamplerV2 is not supported with q-ctrl channel strategy.")
 
     def run(self, pubs: Iterable[SamplerPubLike], *, shots: int | None = None) -> RuntimeJob:
         """Submit a request to the estimator primitive.

qiskit_ibm_runtime/utils/sampler_result_decoder.py

@@ -12,11 +12,12 @@
 
 """Sampler result decoder."""
 
-from typing import Dict
+from typing import Dict, Union
 from math import sqrt
 
 from qiskit.result import QuasiDistribution
 from qiskit.primitives import SamplerResult
+from qiskit.primitives import PrimitiveResult
 
 from .result_decoder import ResultDecoder
 
@@ -25,9 +26,16 @@ class SamplerResultDecoder(ResultDecoder):
     """Class used to decode sampler results."""
 
     @classmethod
-    def decode(cls, raw_result: str) -> SamplerResult:
+    def decode(cls, raw_result: str) -> Union[SamplerResult, PrimitiveResult]:
         """Convert the result to SamplerResult."""
         decoded: Dict = super().decode(raw_result)
+
+        if isinstance(decoded, PrimitiveResult):
+            return decoded
+
+        # TODO: Handle V2 result that is returned in dict format
+
+        # V1 result
         quasi_dists = []
         for quasi, meta in zip(decoded["quasi_dists"], decoded["metadata"]):
             shots = meta.get("shots", float("inf"))