Set an inline `width: auto` for <figure> that has `width: fit-content`.
Set an inline `width: auto` for <figure> that has `width: fit-content`.

A `<figure>` element with `.wp-block-image` and not `.is-resized` has its width set to a default of `fit-content`.  That CSS rule value causes wider images to overflow out of the parent container.  For this element, this commit adds an inline style of `width: auto`.

Closes #1086.

ampproject/amp-toolbox-php,ampproject/amp-toolbox-php