fix: default max_chunks set to 1 as other providers (#10937)

Signed-off-by: yihong0618 <zouzou0208@gmail.com>

api/core/model_runtime/model_providers/volcengine_maas/text_embedding/models.py

         return ModelConfig(
             properties=ModelProperties(
                 context_size=int(credentials.get("context_size", 0)),
-                max_chunks=int(credentials.get("max_chunks", 0)),
+                max_chunks=int(credentials.get("max_chunks", 1)),
             )
         )
     return model_configs