explore removing sync XHR

[stefanpenner]

this one:

ember-inspector/app/adapters/web-extension.js

Line 121 in e3023ae

xhr.open("GET", chrome.runtime.getURL(`/panes-${minimumVersion}/ember_debug.js`), false);

more context: #817

I'm not 100% sure if it is possible to remove this sync XHR, but potentially it could be done in an initializer and defer/advance readiness?

The code in question was added way back in 2013: de62bd6

It is possible this is required, to win some race. but lets ask @teddyzeenny

[teddyzeenny]

This was added in the third ever commit to the inspector. I'm not entirely sure what the reason was for making it sync, but nothing comes to mind as to why async xhr wouldn't work. We can try it.