Revert "[Nearby] Strings updates on contact visibility page."

This reverts commit e859a79a.

Reason for revert: IDS_NEARBY_CONTACT_VISIBILITY_OWN_SOME.png.sha1 is not a sha file.

Original change's description:
> [Nearby] Strings updates on contact visibility page.
>
> Removes the "Contacts" title and updates strings in the description for
> each visibility mode to match the latest specs.
>
> Screenshots:
>   https://screenshot.googleplex.com/An6Ta8EDzfS3KZU.png
>   https://screenshot.googleplex.com/C5WwqifMeCnLhkH.png
>   https://screenshot.googleplex.com/C48HQVfgouJrhHF.png
>
> Strings spec:
>   https://docs.google.com/document/d/1s-KjC1mM4ZPYeYAO7oI8lXltS_1FaYYfMMnNDdbfRag
>
> Bug: b:168841167
> Change-Id: I5facb117242e22b838266c2fa5e2629b221e6794
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2511852


> Reviewed-by: James Vecore <vecore@google.com>
> Commit-Queue: Michael Hansen <hansenmichael@google.com>
> Cr-Commit-Position: refs/heads/master@{#822914}

TBR=vecore@google.com,hansenmichael@google.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: b:168841167
Change-Id: Ie19aa888c3914ac3e65fb330000199023e2a3b54
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2514420


Reviewed-by: Ben Mason <benmason@chromium.org>
Commit-Queue: Ben Mason <benmason@chromium.org>
Cr-Commit-Position: refs/heads/master@{#823159}