Support list indexing in nested template fields

[Gautam-Bharadwaj]

While working with nested template fields, I noticed that _get_nested_value logic only supports dictionary keys and object attributes. This is a limitation when users define sequences/lists in their operator's template fields. I've updated the logic to handle integer keys for list indexing (e.g., list.0).

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[uranusjr]

Sounds reasonable to me. Can you add a test for this?

[Gautam-Bharadwaj]

@uranusjr Thanks for the review! I've added unit tests for _get_nested_value covering dictionary keys, list indexing, and object attributes, as well as an integration test for RTIF. Ready for another look! 👋

[Gautam-Bharadwaj]

Hi @uranusjr ,@potiuk Sir,

Could you please take a look at this PR? If it looks good to you, please feel free to merge it.

Thanks in advance!

[Gautam-Bharadwaj]

@uranusjr plz review this pr