Reenable disabled warnings in third_party/shell-encryption

Fix remaining violations in the codebase and reenable the disabled
warnings and split config so that the internal configuration doesn't
affect the rest of the project.

Fixed: 1095122, 1212837
Change-Id: I37ff46dc53ff291df11450075a644b18c1ce4e10
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3913353
Reviewed-by: Amr Aboelkher <amraboelkher@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Henrique Ferreiro <hferreiro@igalia.com>
Cr-Commit-Position: refs/heads/main@{#1056184}
NOKEYCHECK=True
GitOrigin-RevId: c7faeda445225e9c1eb26db3ed1fe6a2dc5efc17
7 files changed