Refactor count workorders to reuse search code

[jyeshe]

Validation Steps

$ mix test test/lightning/digest_email_worker_test.exs

Notes for the reviewer

As a continuation of #2118:

• Reuse search_workorders_query for counting
• Reuse search_workorders_query to return workorders for retries (with dataclips not wiped)

Keeps same behavior as https://github.com/OpenFn/lightning/pull/2123.

Related issue

Refs #2121

Review checklist

• [x] I have performed a self-review of my code
• [x] I have verified that all appropriate authorization policies (:owner, :admin, :editor, :viewer) have been implemented and tested
• [x] If needed, I have updated the changelog
• [ ] Product has QA'd this feature

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 89.65%. Comparing base (f9f4a5e) to head (3bc24bf).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2122   +/-   ##
=======================================
  Coverage   89.64%   89.65%           
=======================================
  Files         270      270           
  Lines        8953     8942   -11     
=======================================
- Hits         8026     8017    -9     
+ Misses        927      925    -2     

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[jyeshe]

@taylordowns2000 @stuartc this is need to remove duplicated code when searching for workorders and replaces on LV the use of:

socket.assigns.project
|> Invocation.search_workorders_query(filter)
|> Invocation.exclude_wiped_dataclips()
|> Lightning.Repo.all()
|> WorkOrders.retry_many(job_id, ...)

in favor of having query logic on the context module and retrieving only what is needed for retries:

socket.assigns.project
|> Invocation.search_workorders_for_retry(filter)
|> WorkOrders.retry_many(job_id, ...)

where the new function search_workorders_for_retry is similarly defined as: https://github.com/OpenFn/lightning/blob/96848158f0a0d47a3334b0953f83a884b0b524a3/lib/lightning/invocation.ex#L356-L365