fix(android): Regression breaking resolved DOM-usable file:// paths

[breautek]

Platforms affected

Android

Motivation and Context

Regression from 99ca439

Code strips out the file:// protocol for what used to be used by File APIs, but in 8.1.1 that was changed to use CordvaResourceApi which expects an actual valid URI.

Description

If the uri object has no scheme set, then set it to the file scheme.

Testing

paramedic tests passes.
Testing by using camera plugin to capture an image, resolve the file:// uri and attempt to set an image tag src attribute to the fileEntry.toURL() result.

Checklist

• I've run the tests to see all new and existing tests pass
• I added automated test coverage as appropriate for this change
• Commit is prefixed with (platform) if this change only applies to one platform (e.g. (android))
• If this Pull Request resolves an issue, I linked to the issue in the text above (and used the correct keyword to close issues using keywords)
• I've updated the documentation if necessary