Fix confusing error message. (#26157)

We were logging a message about "stop pairing" when the real error was that we
could not get the device being commissioned.

Author: bzbarsky-apple

src/darwin/Framework/CHIP/MTRDeviceController.mm

@@ -548,7 +548,7 @@ - (MTRBaseDevice *)deviceBeingCommissionedWithNodeID:(NSNumber *)nodeID error:(N
         chip::CommissioneeDeviceProxy * deviceProxy;
 
         auto errorCode = self->_cppCommissioner->GetDeviceBeingCommissioned(nodeID.unsignedLongLongValue, &deviceProxy);
-        VerifyOrReturnValue(![MTRDeviceController checkForError:errorCode logMsg:kErrorStopPairing error:error], nil);
+        VerifyOrReturnValue(![MTRDeviceController checkForError:errorCode logMsg:kErrorGetCommissionee error:error], nil);
 
         return [[MTRBaseDevice alloc] initWithPASEDevice:deviceProxy controller:self];
     };