Revert changes to underscore's isEqual (#2125)

## Summary:
[Original comment](#2113 (comment))

I made a separate PR because I made this mistake in a couple of PRs so I thought I'd knock them out all at once.

Issue: LEMS-2737

## Test plan:

Author: handeyeco

Reviewers: jeremywiebe, benchristel

Required Reviewers:

Approved By: jeremywiebe

Checks: ✅ Publish npm snapshot (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), ✅ Cypress (ubuntu-latest, 20.x), ✅ Check builds for changes in size (ubuntu-latest, 20.x), ⏹️  [cancelled] Publish npm snapshot (ubuntu-latest, 20.x), ⏹️  [cancelled] Lint, Typecheck, Format, and Test (ubuntu-latest, 20.x), ⏹️  [cancelled] Check builds for changes in size (ubuntu-latest, 20.x), ⏹️  [cancelled] Cypress (ubuntu-latest, 20.x), ⏹️  [cancelled] Check for .changeset entries for all changed files (ubuntu-latest, 20.x), ⏹️  [cancelled] Publish npm snapshot (ubuntu-latest, 20.x), ⏹️  [cancelled] Check for .changeset entries for all changed files (ubuntu-latest, 20.x), ⏹️  [cancelled] Check builds for changes in size (ubuntu-latest, 20.x), ⏹️  [cancelled] Lint, Typecheck, Format, and Test (ubuntu-latest, 20.x), ⏹️  [cancelled] Cypress (ubuntu-latest, 20.x), ✅ Publish Storybook to Chromatic (ubuntu-latest, 20.x)

Pull Request URL: #2125

packages/perseus-core/src/utils/grapher-util.ts

@@ -1,5 +1,7 @@
 import _ from "underscore";
 
+import {approximateDeepEqual} from "./equality";
+
 import type {
     LinearType,
     QuadraticType,
@@ -95,7 +97,7 @@ const PlotDefaults = {
         coeffs1: ReadonlyArray<number>,
         coeffs2: ReadonlyArray<number>,
     ): boolean {
-        return _.isEqual(coeffs1, coeffs2);
+        return approximateDeepEqual(coeffs1, coeffs2);
     },
     movable: MOVABLES.PLOT,
     getPropsForCoeffs: function (coeffs: ReadonlyArray<number>): {fn: any} {
@@ -269,7 +271,7 @@ const Sinusoid: SinusoidType = _.extend({}, PlotDefaults, {
         coeffs1: ReadonlyArray<number>,
         coeffs2: ReadonlyArray<number>,
     ) {
-        return _.isEqual(
+        return approximateDeepEqual(
             canonicalSineCoefficients(coeffs1),
             canonicalSineCoefficients(coeffs2),
         );
@@ -326,7 +328,7 @@ const Tangent: TangentType = _.extend({}, PlotDefaults, {
         coeffs1: ReadonlyArray<number>,
         coeffs2: ReadonlyArray<number>,
     ) {
-        return _.isEqual(
+        return approximateDeepEqual(
             canonicalTangentCoefficients(coeffs1),
             canonicalTangentCoefficients(coeffs2),
         );

packages/perseus-score/src/widgets/plotter/score-plotter.ts

@@ -1,3 +1,4 @@
+import {approximateDeepEqual} from "@khanacademy/perseus-core";
 import _ from "underscore";
 
 import validatePlotter from "./validate-plotter";
@@ -18,7 +19,7 @@ function scorePlotter(
     }
     return {
         type: "points",
-        earned: _.isEqual(userInput, scoringData.correct) ? 1 : 0,
+        earned: approximateDeepEqual(userInput, scoringData.correct) ? 1 : 0,
         total: 1,
         message: null,
     };

packages/perseus-score/src/widgets/plotter/validate-plotter.ts

@@ -1,3 +1,4 @@
+import {approximateDeepEqual} from "@khanacademy/perseus-core";
 import _ from "underscore";
 
 import type {
@@ -16,7 +17,7 @@ function validatePlotter(
     userInput: PerseusPlotterUserInput,
     validationData: PerseusPlotterValidationData,
 ): ValidationResult {
-    if (_.isEqual(userInput, validationData.starting)) {
+    if (approximateDeepEqual(userInput, validationData.starting)) {
         return {
             type: "invalid",
             message: null,

packages/perseus-score/src/widgets/sorter/score-sorter.ts

@@ -1,3 +1,4 @@
+import {approximateDeepEqual} from "@khanacademy/perseus-core";
 import _ from "underscore";
 
 import validateSorter from "./validate-sorter";
@@ -17,7 +18,7 @@ function scoreSorter(
         return validationError;
     }
 
-    const correct = _.isEqual(userInput.options, rubric.correct);
+    const correct = approximateDeepEqual(userInput.options, rubric.correct);
     return {
         type: "points",
         earned: correct ? 1 : 0,