Image: Shorthand syntax should enable functionality and UI for the lightbox

[artemiomorales]

The following shorthand syntaxes are currently filtered out when specified in theme.json, so we are unable to use them for configuring the lightbox:

"settings": {
    "lightbox": true
}

"settings": {
    "blocks": {
        "core/image": {
            "lightbox": true
         }
    }
}

Presumably, these would be shorthand for the following:

"settings": {
    "lightbox": {
        "enabled": false,
        "allowEditing": true
    }
}

"settings": {
    "blocks": {
        "core/image": {
            "lightbox": {
                "enabled": false,
                "allowEditing": true
            }
         }
    }
}

The following values are likewise filtered out:

"settings": {
    "lightbox": false
}

"settings": {
    "blocks": {
        "core/image": {
            "lightbox": false
         }
    }
}

These could be shorthand for the following:

"settings": {
    "lightbox": {
        "enabled": false,
        "allowEditing": false
    }
}

"settings": {
    "blocks": {
        "core/image": {
            "lightbox": {
                "enabled": false,
                "allowEditing": false
            }
         }
    }
}

We should determine what needs to change in the codebase to allow for this shorthand syntax, determine what the behavior should be, decide whether we should indeed support the shorthand syntax or not and, if so, implement.

[oandregal]

I see how we want to make this more convenient in making it shorter, thanks for thinking about this. At the same time, I also see how some people would expect that lightbox: true to be unfolded into lightbox: { allowEditing: true, enabled: true }.

Moreover, the lightbox feature only works for the image block, so theme authors would not have to write it more than once ever (either at the top-level or the block-level). It's not like they have to write it dozens of times for different blocks. Given all this, I don't think it's worth implementing at the moment.