Can't add an image to the existing album on stream page

Problem/Motivation

When using social_album and I want to add an image to stream using the default /stream page, I see that a field widget is displayed to also add this image to an album, but the options there are always "None" or "Create a new album", even if I already have multiple albums created. So it should be possible to select an existing album.

I have multiple public albums created:

I don't see them in the field widget:

Steps to reproduce

1. Install social_album
2. Create a new public album
3. Go to /stream page and click on 'Add images'
4. Add an image, you should see the `Add image(s) to an album` field widget
5. Try to select an album that you created in step 2.

Proposed resolution

We need to update the custom field widget to allow selecting an existing albums.

Remaining tasks

User interface changes

API changes

Data model changes