feat: Allow skipping of validation when combining workspaces

[lorenzennio]

Description

It would be nice to include the option to avoid the validation step when combining two workspaces:

pyhf/src/pyhf/workspace.py

Line 709 in a1a31f1

def combine(cls, left, right, join='none', merge_channels=False):

Checklist Before Requesting Reviewer

• Tests are passing
• "WIP" removed from the title of the pull request
• Selected an Assignee for the PR to be responsible for the log summary

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For the PR Assignees:

• Summarize commit messages into a comprehensive review of the PR

* Add validate arg to workspace.combine to allow for optionally skipping
  workspace validation during. Default is to validate.
* Add test for validate arg being used.
* Add Lorenz Gaertner to contributors list.

[kratsg]

Is there a reason you want to combine workspaces that don't produce a valid workspace?

[lorenzennio]

Yes, I am working with workspaces that contain instructions for a custom modifier. These don't pass the validation in the first place, but for single workspaces I can simply skip it. Now I want to combine two of them, for a global fit.

[matthewfeickert]

@lorenzennio Can you also add your name to docs /contributors.rst below

pyhf/docs/contributors.rst

Line 35 in a1a31f1

- Jonas Rembser

?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (b4fec1c) 98.28% compared to head (3cafa60) 98.28%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2385   +/-   ##
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  Coverage   98.28%   98.28%           
=======================================
  Files          69       69           
  Lines        4539     4539           
  Branches      803      803           
=======================================
  Hits         4461     4461           
  Misses         45       45           
  Partials       33       33           

Flag	Coverage Δ
contrib	97.86% <100.00%> (ø)
doctest	60.71% <50.00%> (ø)
unittests-3.10	96.29% <100.00%> (ø)
unittests-3.11	96.29% <100.00%> (ø)
unittests-3.8	96.32% <100.00%> (ø)
unittests-3.9	96.34% <100.00%> (ø)

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[matthewfeickert]

Thanks for your PR @lorenzennio — your contributions are appreciated! This all LGTM so I'm just going to push back some style changes that we don't have in the linter yet (nothing wrong with what you did, this is just to reduce noise later when we turn on some additional linting) and then I'll merge. 👍