samples: detect_test: add NULL check for comp_data_blob_handler_new()

comp_data_blob_handler_new() can return NULL on allocation failure.
test_keyword_new() passed the result directly to comp_init_data_blob()
without checking, leading to a NULL pointer dereference. Add the
missing check and route to the existing cd_fail cleanup path,
matching the pattern used by dcblock, google_hotword_detect, and
other blob-using components.

Signed-off-by: Adrian Bonislawski <adrian.bonislawski@intel.com>

Author: abonislawski

src/samples/audio/detect_test.c

@@ -690,6 +690,10 @@ static struct comp_dev *test_keyword_new(const struct comp_driver *drv,
 
 	/* component model data handler */
 	cd->model_handler = comp_data_blob_handler_new(dev);
+	if (!cd->model_handler) {
+		comp_err(dev, "comp_data_blob_handler_new failed");
+		goto cd_fail;
+	}
 
 #if CONFIG_IPC_MAJOR_4
 	/* For IPC4 we only receive the base_cfg, make a copy of it */