feat: merge redirect chains

[cristianoventura]

Description

Currently, when exporting a script, the Studio generates checks for all requests in a redirect chain. For example, the URL http://www.k6.io does 3 redirects.

$ curl -v -L http://www.k6.io 2>&1 | grep -i "^< location:"
< Location: https://www.k6.io/
< location: http://k6.io/index.html
< Location: https://k6.io/index.html

Right now, one check for each request above is generated when exporting the script, which is unexpected behaviour.

This PR introduces logic responsible for identifying and resolving a redirect chain, ensuring that only the initial request and the check for the final response are present.

Example: Request to http://www.k6.io (first request in the chain) checks for the response in https://k6.io/index.html (final response in the chain).

How to Test

• Create a recording and browse to a website that does at least one redirect, such as http://www.k6.io (note the HTTP protocol)
• Check the redirect chain in the request list
  
• Export a script and verify that only one check is present (checking for the HTTP status of the last request in the chain)

Checklist

• I have performed a self-review of my code.
• I have added tests for my changes.
• I have run linter locally (npm run lint) and all checks pass.
• I have run tests locally (npm test) and all tests pass.
• I have commented on my code, particularly in hard-to-understand areas.

Related PR(s)/Issue(s)

Resolves #206