Allow access from File urls

[devxpy]

If one tries to load html from android assets, the following error is presented

 WebviewScaffold(
  url: 'file:///android_asset/pdfjs/web/viewer.html',
),

I/chromium(  645): [INFO:CONSOLE(3933)] "Failed to load file:///android_asset/pdfjs/web/locale/locale.properties: Cross origin requests are only supported for protocol schemes: http, data, chrome, https.", source: file:///android_asset/pdfjs/web/viewer.js (3933)

According to this answer, we can use setAllowFileAccessFromFileURLs() to fix this.

Can we have similar functionality in this plugin?

+1

@devxpy thanks for this fix. Will help me but i think a ton of others..