feat(integrations): Check if any nulls in reshape output

[topher-lo]

What changed

• Added support to raise error, raise error with check (i.e. jsonpaths that lead to null values), and drop nulls in core.transform.reshape action
• check is super powerful because it turns a list of jsonpaths / dot notation to the fields with nulls e.g:

Null values encountered in output. Found null values in the following fields:

 - metadata.updated_by
 - items[0].nested.values[1]
 - items[1].nested

It even supports lists indexing and fields with special characters e.g. items[0]."this is some".field

Why do we need this

Reshape is often used to organize / transform data from upstream (i.e. from an alert) into a flatter / more readable object. This is then used in downstream tasks (e.g. post notification to Slack, open Jira ticket).

We want to raise an error with informative message (for fast and easy debugging) if there any any nulls.

QA

Added unit tests and created simple PoC workflow, which expects ip but receives ip_address field instead. We pass the error message to Claude to explain.