Create alt text automator field widget

Problem/Motivation

The base work for getting field widget is done in ✨ Add processor and field widget assist plugin system to AI Content Suggestions Active - now we need to start adding widgets for the automator fields.

We should start with some weirder widgets, to see that the architecture handles all of them - we start with alt text.

The file already exists there, we just have to make sure it only triggers when an image appear.

Proposed resolution

Add all the functionality for the alt text automator widget.