test: improve jest configuration

[djskinner]

Goal

Simplify the jest testing configuration and fix the following warning in the test output:

ReferenceError: You are trying to `import` a file after the Jest environment has been torn down.

      at get (node_modules/react-native/Libraries/Core/setUpXHR.js:28:30)
      at Object.getValue [as Blob] (node_modules/react-native/Libraries/Utilities/defineLazyObjectProperty.js:42:16)
          at Array.forEach (<anonymous>)

Design

Remove unnecessary configuration. Specify own minimal test setup.

Changeset

• Removal of setUpGlobals.js and setUpXHR.js test setup for react-native tests
• Define window in test setup, which is the only thing we used from setUpGlobals.js
• Remove unnecessary ts configuration

Testing

Automated tests pass

[bugsnagbot]

@bugsnag/browser bundle size diff

	Minified	Minfied + Gzipped
Before	39.62 kB	12.23 kB
After	39.62 kB	12.23 kB
±	No change	No change

Generated by 🚫 dangerJS against b1645ce

[bengourley]

apparently i thought this was necessary for the rn integration tests 83bbb38#diff-2d0cd5d10b9604941c38c6aac608178a

but since they still pass on this branch, it seems it is not required

[bengourley]

how come these are no longer required?

[djskinner]

I'm afraid I can't remember fully. I think added when I was working through the clashing of @types/react and @types/react-native