Remove refs to obsolete NaCl Mozc packages in ebuild_sizing.

This is a follow-up to https://crrev.com/c/6663207
where Japanese IME / NaCl Mozc packages were removed
from open-source ChromiumOS.

BUG=b:425767969
TEST=None

Change-Id: Ia8122f44d8dc95294009d93315248a53cebf0ab0
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/bazel/+/6864359
Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>
Tested-by: Bao-Duy Tran <tranbaoduy@chromium.org>
Reviewed-by: Matt Stark <msta@google.com>
Commit-Queue: Bao-Duy Tran <tranbaoduy@chromium.org>