fix: Add missing type administrative_area_level_6 and administrative_area_level_7

[gpradhan27]

This PR adds the missing AddressComponentType administrative_area_level_6 and administrative_area_level_7 - the java doc comments for enum types were copied from https://developers.google.com/maps/documentation/geocoding/requests-geocoding , hope this is the correct one.

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Fixes #985 🦕

[gpradhan27]

hi @wangela could you please review this?