[SR] Update Circle strings

[nishasy]

Summary:

We're doing a final pass on strings now at the end of the phase 1
interactive graph screen reader work.

• Update the circle radius point’s label to “<Right/Left> radius endpoint at ."

Issue: https://khanacademy.atlassian.net/browse/LEMS-2782

Test plan:

yarn jest packages/perseus/src/widgets/interactive-graphs/graphs/circle.test.tsx

Storybook

• http://localhost:6006/?path=/story/perseuseditor-widgets-interactive-graph--interactive-graph-circle

[github-actions]

npm Snapshot: Published

Good news!! We've packaged up the latest commit from this PR (ba885af) and published it to npm. You
can install it using the tag PR2250.

Example:

yarn add @khanacademy/perseus@PR2250

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

./dev/tools/bump_perseus_version.sh -t PR2250

[github-actions]

Size Change: +81 B (+0.01%)

Total Size: 1.47 MB

Filename	Size	Change
packages/perseus/dist/es/index.js	368 kB	+48 B (+0.01%)
packages/perseus/dist/es/strings.js	6.61 kB	+33 B (+0.5%)

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	77.7 kB
packages/math-input/dist/es/strings.js	1.79 kB
packages/perseus-core/dist/es/index.js	48.2 kB
packages/perseus-editor/dist/es/index.js	689 kB
packages/perseus-linter/dist/es/index.js	22.1 kB
packages/perseus-score/dist/es/index.js	115 kB
packages/pure-markdown/dist/es/index.js	3.66 kB
packages/simple-markdown/dist/es/index.js	12.5 kB

_{compressed-size-action}

[catandthemachines]

LGTM, let's go 😉