[App Management] Rename |item| to |app_item|

This CL renamed item element to app_item so that it won't be confused with permission_item.

Bug: 906508
Change-Id: I6e5edc7eb592d2f455ad106cec3cd7fb65fe6ebf
Reviewed-on: https://chromium-review.googlesource.com/c/1429315
Commit-Queue: Cecilia Ni <ceciliani@google.com>
Reviewed-by: calamity <calamity@chromium.org>
Reviewed-by: Eric Willigers <ericwilligers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#625890}
8 files changed