[FEATURE] CreateIngestPipelineStep Improvements

[joshpalis]

Is your feature request related to a problem?

In an effort to address any issues/gaps with the current step implementations, this issue is to track necessary modifications for the CreateIngestPipelineStep.

• The use case template workflow parser is responsible for populating the WorkflowData that each WorkflowStep will read information from to execute their function. Modify how the CreateIngestPipelineStep currently reads data from the WorkflowData to ensure that the expected information is read correctly. The following example WorkflowData is what is generated from the following use case template section.

Use Case Template Create Ingest Pipeline Section :

{
    "id": "create_ingest_pipeline",
    "type": "create_ingest_pipeline",
    "inputs": {
      "id": "my-ingest-pipeline",
      "description": "some description",
      "processors": [
        {
          "type": "text_embedding",
          "params": {
            "model_id": "my-existing-model-id",
            "input_field_name": "text_passage",
            "output_field_name": "text_embedding"
          }
        }
      ]
    }
  }

WorkflowData :

{
    description=some description,
    id=my-ingest-pipeline, 
    processors=[Lorg.opensearch.flowframework.model.PipelineProcessor;
}

Note : The PipelineProcessor (link) contains the type and a list of required parameters for this type. In the case of the text-embedding processor, the required parameters are the model_id, 'input_field_name', 'output_field_name'.

[amitgalitz]

Done with #558