Added an optional workflow_step param to the get workflow steps API

[owaiskazi19]

Description

Added an optional workflow_step param to the get workflow steps API.

Request:

GET localhost:9200/_plugins/_flow_framework/workflow/_steps?workflow_step=create_connector,delete_model,deploy_model

Response:

{
    "create_connector": {
        "inputs": [
            "name",
            "description",
            "version",
            "protocol",
            "parameters",
            "credential",
            "actions"
        ],
        "outputs": [
            "connector_id"
        ],
        "required_plugins": [
            "opensearch-ml"
        ],
        "timeout": "1m"
    },
    "deploy_model": {
        "inputs": [
            "model_id"
        ],
        "outputs": [
            "model_id"
        ],
        "required_plugins": [
            "opensearch-ml"
        ],
        "timeout": "15s"
    },
    "delete_model": {
        "inputs": [
            "model_id"
        ],
        "outputs": [
            "model_id"
        ],
        "required_plugins": [
            "opensearch-ml"
        ]
    }
}

Issues Resolved

Resolves #456

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[dbwiddis]

Looks good. A few suggestions to make it better.

[codecov]

Codecov Report

Attention: Patch coverage is 79.16667% with 5 lines in your changes are missing coverage. Please review.

Project coverage is 73.83%. Comparing base (3923f34) to head (3429ac3).

Files	Patch %	Lines
...work/transport/GetWorkflowStepTransportAction.java	66.66%	3 Missing ⚠️
.../flowframework/rest/RestGetWorkflowStepAction.java	60.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #538      +/-   ##
============================================
+ Coverage     73.10%   73.83%   +0.73%     
- Complexity      649      663      +14     
============================================
  Files            79       79              
  Lines          3294     3314      +20     
  Branches        257      263       +6     
============================================
+ Hits           2408     2447      +39     
+ Misses          773      752      -21     
- Partials        113      115       +2     

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