Add missing filters for: Cadence, Iteration

What does this MR do and why?

This MR adds iteration filtering capabilities to the Work Items GraphQL API, bringing it to feature parity with the Issues API. It allows users to filter work items by iterations, iteration wildcards, and iteration cadences.

Changes

• GraphQL API Updates:

  • Added iteration_ids argument to filter work items by specific iterations (accepts both raw IDs and Global IDs)
  • Added iteration_wildcard_id argument to filter by iteration wildcards (CURRENT, ANY, NONE)
  • Added iteration_cadence_ids argument to filter work items by iteration cadences
  • Added iteration_ids to the negated filter input type for excluding specific iterations
  • Implemented mutual exclusivity validation between iteration_ids and iteration_wildcard_id

• Implementation Details:

  • Used plural naming convention for array fields (iteration_ids, iteration_cadence_ids) for better API consistency
  • Added parameter transformation in prepare_finder_params to convert plural GraphQL argument names to singular finder parameter names as supported by the finder

References

Relates to #546400 (closed), #510269 (closed)

Screenshots or screen recordings

Before	After

How to set up and validate locally

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