Don't show ungraded text for 'none' graph

[handeyeco]

Summary:

Small change to hide "ungraded" text when a graph is "none" type (which is already not graded).

See: https://khanacademy.slack.com/archives/C05MUPEJUPP/p1780076351228929

[github-actions]

npm Snapshot: Published

Good news!! We've packaged up the latest commit from this PR (08b9b42) and published it to npm. You
can install it using the tag PR3691.

Example:

pnpm add @khanacademy/perseus@PR3691

If you are working in Khan Academy's frontend, you can run the below command.

./dev/tools/bump_perseus_version.ts -t PR3691

If you are working in Khan Academy's webapp, you can run the below command.

./dev/tools/bump_perseus_version.js -t PR3691

[github-actions]

Size Change: +17 B (0%)

Total Size: 506 kB

📦 View Changed

Filename	Size	Change
packages/perseus/dist/es/index.js	199 kB	+17 B (+0.01%)

ℹ️ View Unchanged

Filename	Size
packages/kas/dist/es/index.js	20.6 kB
packages/keypad-context/dist/es/index.js	1 kB
packages/kmath/dist/es/index.js	6.32 kB
packages/math-input/dist/es/index.js	98.5 kB
packages/math-input/dist/es/strings.js	1.61 kB
packages/perseus-core/dist/es/index.item-splitting.js	12.1 kB
packages/perseus-core/dist/es/index.js	26.1 kB
packages/perseus-editor/dist/es/index.js	105 kB
packages/perseus-linter/dist/es/index.js	9.41 kB
packages/perseus-score/dist/es/index.js	10.2 kB
packages/perseus-utils/dist/es/index.js	403 B
packages/perseus/dist/es/strings.js	8.55 kB
packages/pure-markdown/dist/es/index.js	1.39 kB
packages/simple-markdown/dist/es/index.js	6.71 kB

_{compressed-size-action}

[ivyolamit]

LGTM 👍🏼