Make MSW work well (Network stubbing/interception)

[calebeby]

MSW is a library for request interception. https://mswjs.io/

Here is a Kent article that explains why it is good.

Puppeteer has a built-in way to do request interception. But MSW's API is nicer and more intuitive.

We should look into either:

• Getting MSW to work with Pleasantest
• Make an API that looks and works like MSW that actually just wraps Puppeteer's request interception

[calebeby]

Also worth looking into Cypress's API's for route interception and see if they have any good ideas that we can learn from, for example https://docs.cypress.io/api/commands/intercept.html looks pretty nice