fix: ADO single and multi file tests

[cuserox]

Why does this PR exist?

Closes #3085

What does this pull request do?

Changes to the way that ADO works meant that the fetch mocks had to be updated to test the functionality correctly

Testing this change

Run the tests (or see them in the pipeline) - see that ADOTokenStorageTest.ts ✅

[changeset-bot]

⚠️ No Changeset found

Latest commit: 8206c96

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

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[github-actions]

⤵️ 📦 ✨ The artifact was successfully created! Want to test it? Download it here 👀 🎁

[github-actions]

Commit SHA:4648b18903b2a8eed43fae531aa7ada6d7f353af

Test coverage results 🧪

Code coverage diff between base branch:main and head branch: fix/3085-update-ado-related-tests 

Status	File	% Stmts	% Branch	% Funcs	% Lines
🟢	total	67.91 (0.27)	58.59 (0.19)	64.56 (0.23)	68.31 (0.26)
🟢	packages/tokens-studio-for-figma/src/storage/ADOTokenStorage.ts	81.74 (26.19)	63.52 (18.82)	80.64 (22.58)	84.03 (26.05)

[macintoshhelper]

LGTM. One comment re changeset for tests, not sure if this would be (or whether it should be) surfaced for the 2.0.2 changelog