Revert svg-image changes (#2001)

## Summary:
Undoing svg image changes to unblock Perseus. 

## Test plan:
- simple revert.

Author: SonicScrewdriver

Reviewers: mark-fitzgerald

Required Reviewers:

Approved By: mark-fitzgerald

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

Pull Request URL: #2001

.changeset/smooth-hairs-jam.md

@@ -0,0 +1,5 @@
+---
+"@khanacademy/perseus": minor
+---
+
+Undoing changes to svg-image

packages/perseus/src/__tests__/renderer.test.tsx

@@ -63,14 +63,6 @@ describe("renderer", () => {
         jest.spyOn(Dependencies, "getDependencies").mockReturnValue(
             testDependencies,
         );
-
-        // Mocked for loading graphie in svg-image
-        global.fetch = jest.fn(() =>
-            Promise.resolve({
-                text: () => "",
-                ok: true,
-            }),
-        ) as jest.Mock;
     });
 
     afterEach(() => {