Summary:
@public
The API and implementation of `shouldInjectAJAXHandler` is very opinionated, and it does not solve many of the use cases that we'd like to address.
Since `shouldInjectAJAXHandler` is basically juts injecting JS to the web page, we should let developer inject whatever JS that address different issues that they want to fix.
Test Plan:
Test this snippet at <Playground />
```
<WebView
url="http://www.facebook.com"
injectedJavascriptIOS="document.body.style.border='solid 10px red'"
/>
```
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