feat(enhanced-img): add "display: contents" on the picture element

[blt-r]

This is technically a breaking change. Closes #11017.

This allows enhanced:img to be styled as a grid/flex element.

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[vladshcherbin]

It's also possible to just use a global style for picture 🤔

[blt-r]

well that would affect user's own picture's, i don't think that's desired at all