Broken in Apple lockdown mode

[GarboMuffin]

Latest Safari on macOS and iPad OS:

TypeError: n.arrayBuffer is not a function. (In 'n.arrayBuffer()', 'n.arrayBuffer' is undefined)

Not clear why that is not working. fetch() and Response#arrayBuffer() seem to work fine in brief unit test.

Given that no one had ever reported before it seem not many people use lockdown mouse so probably not too urgent to fix

[GarboMuffin]

we use cross-fetch which uses whatwg-fetch in web environment. whatwg-fetch requires FileReader to exist for Blob support, Blob support required for its Response#arrayBuffer().

at this point there is not really any reason for us to be using a polyfill. we can just use native fetch and avoid this