Minor fixes.

* remove a check that was inadvertently kept.
* print a log message when something that shouldn't happen inevitably does.
* use user_params to get the end user support log test parameter.

src/controller/python/chip/bdx/bdx-transfer.cpp

@@ -71,8 +71,6 @@ CHIP_ERROR BdxTransfer::Reject()
 
 void BdxTransfer::HandleTransferSessionOutput(TransferSession::OutputEvent & event)
 {
-    assertChipStackLockedByCurrentThread();
-
     ChipLogDetail(BDX, "Received event %s", event.ToString(event.EventType));
 
     switch (event.EventType)
@@ -124,6 +122,7 @@ void BdxTransfer::HandleTransferSessionOutput(TransferSession::OutputEvent & eve
         break;
     default:
         // Should never happen.
+        ChipLogError(BDX, "Unhandled BDX transfer session event type %d.", static_cast<int>(event.EventType));
         chipDie();
         break;
     }

src/python_testing/TestBdxTransfer.py

@@ -86,7 +86,7 @@ async def test_bdx_transfer(self):
         data = await bdx_transfer.accept()
 
         self.step(6)
-        data_file = open(self.matter_test_config.global_test_params["end_user_support_log"], "rb")
+        data_file = open(self.user_params["end_user_support_log"], "rb")
         asserts.assert_equal(bytearray(data), data_file.read(), "Transferred data doesn't match")
 
         self.step(7)