feat(ios): support file scheme

Platforms affected

iOS platform

Motivation and Context

In iOS, this plugin does not support file:// scheme. Therefore following code does not work

  window.requestFileSystem(
      LocalFileSystem.PERSISTENT,
      0,
      function (fs) {
          const pathPrefix = fs.root.toURL();
          file = pathPrefix + fileName;
          mediaRec = new Media(file, mediaRecordSuccess, mediaError, mediaRecordStatus);
          mediaRec.startRecord();
      },
      function (err) {
          alert("LocalFileSystem Error");
      }
  );

On the other hand, this code works in Android.

The actual file variable in the above code is like file:///var/mobile/Containers/Data/Application/6DAC6E88-C38A-4A8B-A7E9-456345E5D25D/Library/NoCloud/myrecording.m4a where the file:// scheme is used. But the current this plugin does not support file:// scheme in iOS and not work in iOS.

This is inconsistent with in Android.

Description

This PR improves Media plugin to support file:// scheme in iOS.

Testing

In my local Mac, I create a sample cordova project and add this modified media plugin. Check the Recording and Playing audio with file path using file:// scheme and confirm it works well.

Checklist

[ ] I've run the tests to see all new and existing tests pass
[ ] I added automated test coverage as appropriate for this change
[x] 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

apache / cordova-plugin-media