(android) Use decoded path when querying file list in directory via assetManager

[jhlee8804]

Platforms affected

Android

Motivation and Context

The problem is that subfiles and folders cannot be listed via the assetManager.list function
if the folder name has special characters like @havesource.

# Folder Tree
www/plugins/@havesource/
  ㄴ cordova-plugin-push
      ㄴ www
          ㄴpush.js

Description

The AssetManager.list function does not automatically decode the passed paths that are encoded.
So if the folder name has special characters (such as @), it can't listing subfolders and files.

Testing

We need to pass the decoded path to the assetManager.list function.
Then the assetManager.list function returns a list of subfolders and files successfully.

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