Upgrade node-fetch to v3.1.1

[sherryhli]

User Story and Context

We have a dependabot PR that upgrades node-fetch to v3.1.1 which needs to be merged. The catch is that this is a major version upgrade that introduces breaking changes. In particular, the typing of the .json() method on HTTP responses has changed from Promise<any> to Promise<unknown> and this is incompatible with our current usage in backend/utilities/firebaseRestClient.ts. Please resolve these issues and then merge the PR.

Acceptance Criteria

• Resolve typing issues in backend/utilities/firebaseRestClient.ts resulting from the node-fetch upgrade
• Ensure that there are no other breaking changes (you will want to test the sign-in, sign-in with Google, and refresh token functionalities)

Dev Notes

• Check the GitHub Actions log for details of the error
• Please commit the resolution on the same branch as the dependabot upgrade

[MatoPlus]

On closer inspection. The type errors stated in CI are not the only errors. node-fetch from v3 is an ESM-only module - we cannot import it with require().

I'm running into some weird behaviour locally after doing the migration:

backend_1   | Error [ERR_REQUIRE_ESM]: Must use import to load ES Module: /app/node_modules/node-fetch/src/index.js
backend_1   | require() of ES modules is not supported.
backend_1   | require() of /app/node_modules/node-fetch/src/index.js from /app/utilities/firebaseRestClient.ts is an ES module file as it is a .js file whose nearest parent package.json contains "type": "module" which defines all .js files in that package scope as ES modules.
backend_1   | Instead rename index.js to end in .cjs, change the requiring code to use import(), or remove "type": "module" from /app/node_modules/node-fetch/package.json.
backend_1   | 
backend_1   |     at Object.Module._extensions..js (internal/modules/cjs/loader.js:1080:13)
backend_1   |     at Module.load (internal/modules/cjs/loader.js:928:32)
backend_1   |     at Function.Module._load (internal/modules/cjs/loader.js:769:14)
backend_1   |     at Module.require (internal/modules/cjs/loader.js:952:19)
backend_1   |     at require (internal/modules/cjs/helpers.js:88:18)
backend_1   |     at Object.<anonymous> (/app/utilities/firebaseRestClient.ts:1:1)
backend_1   |     at Module._compile (internal/modules/cjs/loader.js:1063:30)
backend_1   |     at Module.m._compile (/app/node_modules/ts-node/src/index.ts:1295:23)
backend_1   |     at Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
backend_1   |     at Object.require.extensions.<computed> [as .ts] (/app/node_modules/ts-node/src/index.ts:1298:12)
backend_1   | [nodemon] app crashed - waiting for file changes before **starting...**