Feature/4628 search for articles to add

[amoedoamorim]

Description

Introduces the ChooseExistingArticleButton

References: CV2-4628

Type of change

• Performance improvement and/or refactoring (non-breaking change that keeps existing functionality)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Security mitigation or enhancement
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Automated test (add or update automated tests)

How has this been tested?

Tested manually locally and added unit test for the open slideout functionality.
To test locally go to the new articles tab on an item and verify the new "Choose existing article button"

Things to pay attention to during code review

Please describe parts of the change that require extra attention during code review, for example:

• File FFFF, line LL: This refactoring does this and this. Is it consistent with how it’s implemented elsewhere?
• Etc.

Checklist

• I have performed a self-review of my own code
• I've made sure my branch is runnable and given good testing steps in the PR description
• I considered secure coding practices when writing this code. Any security concerns are noted above.
• I have commented my code in hard-to-understand areas, if any
• I have made needed changes to the README
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• If I implemented any new components, they are self-contained, their propTypes are declared and they use React Hooks and, if data-fetching is required, they use Relay Modern with fragment containers
• If my components involve user interaction - specifically button, text fields, or other inputs - I have added a BEM-like class name to the element that is interacted with
• To the best of my knowledge, any new styles are applied according to the design system
• If I added a new external dependency, I included a rationale for doing so and an estimate of the change in bundle size (e.g., checked in https://bundlephobia.com/)

[brianfleming]

This is great progress @amoedoamorim

one thing that I didn't put into the designs (my oversight) is an "empty" message for when the search doesn't match anything.

I can put together designs if it's easier for you, let me know.
but my thought is to use the same styles that Caio added for the empty articles message. I believe the className is articlesSidebarNoArticle
however with the text:
No results matched your search.

Let me know if you have any questions.

[danielevalverde]

Code and functionality look good to me

[brianfleming]

thanks for adding the empty state @amoedoamorim !