Switch from using useRef() to createRef()

[jeremywiebe]

Summary:

I noticed a test that was jumping through hoops with spies in order to manage a ref in tests. Using React.createRef() is simpler and avoids needing to mock a hook.

Issue: "none"

Test plan:

yarn test ✅

[khan-actions-bot]

Gerald

Required Reviewers

• @Khan/perseus for changes to packages/perseus-editor/src/widgets/__tests__/interactive-graph-editor.test.tsx

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[github-actions]

npm Snapshot: Published

Good news!! We've packaged up the latest commit from this PR (71a7ef4) and published it to npm. You
can install it using the tag PR1603.

Example:

yarn add @khanacademy/perseus@PR1603

If you are working in Khan Academy's webapp, you can run:

./dev/tools/bump_perseus_version.sh -t PR1603

[github-actions]

Size Change: 0 B

Total Size: 859 kB

ℹ️ View Unchanged

Filename	Size
packages/kas/dist/es/index.js	38.3 kB
packages/keypad-context/dist/es/index.js	760 B
packages/kmath/dist/es/index.js	4.27 kB
packages/math-input/dist/es/index.js	78 kB
packages/math-input/dist/es/strings.js	1.79 kB
packages/perseus-core/dist/es/index.js	1.48 kB
packages/perseus-editor/dist/es/index.js	275 kB
packages/perseus-linter/dist/es/index.js	22.2 kB
packages/perseus/dist/es/index.js	417 kB
packages/perseus/dist/es/strings.js	3.36 kB
packages/pure-markdown/dist/es/index.js	3.66 kB
packages/simple-markdown/dist/es/index.js	12.4 kB

_{compressed-size-action}

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.43%. Comparing base (eddcb94) to head (71a7ef4).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1603      +/-   ##
==========================================
- Coverage   70.52%   70.43%   -0.09%     
==========================================
  Files         547      572      +25     
  Lines      107037   111539    +4502     
  Branches     5532    11867    +6335     
==========================================
+ Hits        75485    78563    +3078     
- Misses      31436    32976    +1540     
+ Partials      116        0     -116     

see 1119 files with indirect coverage changes

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[aemandine]

LGTM and this makes sense, no re-renders so createRef won't do any unwanted overwriting! Thanks for doing this, got me to look up the difference between useRef and createRef:)