[OsSettingsLanguages] Add enhanced and customize spell check

Adding click handler for customize spell check in follow-up CL.

DisabledView: http://screen/BwJ7YNftynvYNVN
EnabledView: http://screen/5kcJNdQhrF8Foq5
Spec: http://go/cros-lang-settings-ux-slide/edit#slide=23

Note: All strings are not finalised so they are translateable false
and no screenshots required.

Bug: 1113439
Change-Id: Ibdc7fb40cb70d3ffd670e9e1a8bff84764a229e6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2362044


Commit-Queue: My Nguyen <myy@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Reviewed-by: Regan Hsu <hsuregan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#805665}