fix(android): Fix picking from 'SDCARD' location

[xuhcc]

PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
• All existing tests are passing
• Tests for the changes are included

What is the current behavior?

Picking files from SDCARD location doesn't work. Here's an example of the selection result:

[{
  "_observers": {},
  "_options": {
    "keepAspectRatio": true,
    "autoScaleFactor": true
  },
  "_android": ""
}]

What is the new behavior?

Now it's working (at least in some cases).

[NathanWalker]

Thank you @xuhcc