Onboard search req / search resp ML processors

[ohltyler]

Description

This PR adds ML processor as options in the context of search request and search response. Additionally, it finishes all of the logic in the input transform / output transform modals to dynamically fetch input / generate output. There are a few places where this preview / advanced transform view is gated:

1. Chaining multiple search request processors - in this case, since we don't have per-processor logging available, we cannot generate the interim transformed request. This is already tracked here: [Feature Request] Support a verbose/debugging param in search pipelines OpenSearch#14745
2. Advanced output transform for search request processors - we cannot do partial simulation of the search request processor in the context of output transformations, since there is no way to configure a working, simulate-able search request processor with an empty output_map - it is always required, as both input_map and output_map are optional in the context of ingest and search response. We need an empty output_map in order to isolate the response up to the point of configuring it.

More implementation details:

• finishes handling the different contexts in InputTransformModal and the logic needed to fetch inputs
• finishes handling the different contexts in OutputTransformModal and the logic needed to fetch inputs
• refactors formikToIngestPipeline -> formikToPartialPipeline to be generic and handle for all contexts
• adds gating in MLProcessorInputs to enable/disable the Preview button based on the different scenarios mentioned above ^
• extra limitations on search request processor contexts: the input maps and output maps are required: warning modal added when these are empty
• minor change in formatting of search responses to just show the nested _source document info. This is also to keep consistent with how the ML inference processors handle this input JSON, so we can replicate it correctly & consistently in the transform modals.

Testing:

• Both added ML processors compile and work as expected, and generate valid search template resources
• Preview works for both
• Preview is disabled based on 2 scenarios above
• Existing ingest processor & preview works as expected

Demo video, showing the 2 new processors, and preview functionality for both.

screen-capture.17.webm

Issues Resolved

Resolves #217
Makes progress on #23
Makes progress on #219

Check List

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