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455a7448 - community[patch]: Invoke callback prior to yielding token (sparkllm) (#18625)

community[patch]: Invoke callback prior to yielding token (sparkllm) (#18625) ## PR title community[patch]: Invoke callback prior to yielding token ## PR message - Description: Invoke callback prior to yielding token in _stream_ method in llms/sparkllm. - Issue: #16913 - Dependencies: None