Add mafs.point flag to Renderer prop types (#1386)

## Summary:
Perseus renders point graphs with fixed numbers of points using Mafs
when the `mafs.point` flag is on. Previously, however, the apiOptions
type (used in the Renderer props) did not allow this flag to be passed.
This commit makes it so the flag can be passed without a type error.

Issue: none

## Test plan:

- Check out this webapp PR: Khan/webapp#23239
- Upgrade Perseus to the dev version built by CI for this pull request.
- Run the typechecker in webapp's static service.
- There should be no errors.

Author: benchristel

Reviewers: nishasy, #perseus, mark-fitzgerald, SonicScrewdriver

Required Reviewers:

Approved By: nishasy

Checks: ✅ codecov/project, ✅ codecov/patch, ✅ Upload Coverage (ubuntu-latest, 20.x), ✅ Publish npm snapshot (ubuntu-latest, 20.x), ✅ Lint, Typecheck, Format, and Test (ubuntu-latest, 20.x), ✅ Jest Coverage (ubuntu-latest, 20.x), ✅ Check for .changeset entries for all changed files (ubuntu-latest, 20.x), ✅ Cypress (ubuntu-latest, 20.x), ✅ Check builds for changes in size (ubuntu-latest, 20.x), ✅ gerald, ❌ Upload Coverage (ubuntu-latest, 20.x), ✅ Publish npm snapshot (ubuntu-latest, 20.x), ✅ Check builds for changes in size (ubuntu-latest, 20.x), ✅ Lint, Typecheck, Format, and Test (ubuntu-latest, 20.x), ✅ Check for .changeset entries for all changed files (ubuntu-latest, 20.x), ✅ Jest Coverage (ubuntu-latest, 20.x), ✅ Cypress (ubuntu-latest, 20.x), ✅ Publish Storybook to Chromatic (ubuntu-latest, 20.x), ✅ gerald

Pull Request URL: #1386

.changeset/curvy-singers-check.md

@@ -0,0 +1,5 @@
+---
+"@khanacademy/perseus": minor
+---
+
+Add `mafs.point` flag to ApiOptions type

packages/perseus/src/types.ts

@@ -134,14 +134,16 @@ export const MafsGraphTypeFlags = [
     "linear-system",
     /** Enables the `ray` interactive-graph type.  */
     "ray",
-    /** Enables the `polygon` interactive-graph type.  */
+    /** Enables the `polygon` interactive-graph type a fixed number of sides. */
     "polygon",
     /** Enables the `circle` interactive-graph type.  */
     "circle",
     /** Enables the `quadratic` interactive-graph type.  */
     "quadratic",
     /** Enables the `sinusoid` interactive-graph type.  */
     "sinusoid",
+    /** Enables the `point` interactive-graph type with a fixed number of points. */
+    "point",
 ] as const;
 
 export const InteractiveGraphLockedFeaturesFlags = [