Create helper to build public widget options for Plotter

[Myranae]

Summary:

Adds a function that takes Plotter's full widget options and filters out answer data. It also adds this function to Plotter's widget export and adds a test confirming the function works as intended.

Issue: LEMS-2764

Test plan:

• Confirm all checks pass
• Confirm Plotter still works as expected

[github-actions]

npm Snapshot: Published

Good news!! We've packaged up the latest commit from this PR (4a6982d) and published it to npm. You
can install it using the tag PR2216.

Example:

yarn add @khanacademy/perseus@PR2216

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

./dev/tools/bump_perseus_version.sh -t PR2216

[github-actions]

Size Change: +48 B (0%)

Total Size: 1.48 MB

Filename	Size	Change
packages/perseus-core/dist/es/index.js	46.3 kB	+32 B (+0.07%)
packages/perseus/dist/es/index.js	379 kB	+16 B (0%)

ℹ️ View Unchanged

Filename	Size
packages/kas/dist/es/index.js	39 kB
packages/keypad-context/dist/es/index.js	760 B
packages/kmath/dist/es/index.js	86.9 kB
packages/math-input/dist/es/index.js	77.6 kB
packages/math-input/dist/es/strings.js	1.79 kB
packages/perseus-editor/dist/es/index.js	688 kB
packages/perseus-linter/dist/es/index.js	22.2 kB
packages/perseus-score/dist/es/index.js	115 kB
packages/perseus/dist/es/strings.js	6.06 kB
packages/pure-markdown/dist/es/index.js	3.66 kB
packages/simple-markdown/dist/es/index.js	12.5 kB

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[benchristel]

LGTM!