Migrate test setup scripts from js to ts

[devaradhanm]

Describe the bug

We were using js for global setup & teardown files for jest due to this bug - jestjs/jest#5164
But, this issue is fixed now. So, we can move to typescript now.

To Reproduce
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1. Go to '...'
2. Click on '...'
3. Scroll down to '...'
4. See error

Expected behavior

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Extension (please complete the following information)

• OS: [e.g. Windows/Mac]
• Version [e.g. 1.140.1]
• Chrome Version [e.g 71.0]
• Target Page [e.g www.bing.com]

Are you willing to submit a PR?

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Did you search for similar existing issues?

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Additional context

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