Don't try to trigger notification attribution for all default apps.

Unless a default app has actually been installed (and thus an app shim
exists) we should not be trying to use notification attribution for
these (as that will fail in a not great way).

Bug: 330856243
Include-Ci-Only-Tests: true
Change-Id: Idbae227e0ffddf8d8d6b5e268755f60d3fe29a23
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5386826


Reviewed-by: Daniel Murphy <dmurph@chromium.org>
Reviewed-by: Justin DeWitt <dewittj@chromium.org>
Reviewed-by: Elias Klim <elklm@chromium.org>
Commit-Queue: Marijn Kruisselbrink <mek@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1280291}