fix(gatsby-source-contentful): add missing "face" crop focus option (#13364)
fix(gatsby-source-contentful): add missing "face" crop focus option (#13364)

## Description

There’s another crop focus option called `face` that isn’t in the plugin yet.

Reference:
https://www.contentful.com/developers/docs/references/images-api/#/reference/resizing-&-cropping/specify-focus-area
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