[AppIntegration] Fix Settings isn't shown on third party device.

The bug was due to if the opt in card is disabled by default on the
third party device, we will not create and init donor. Thus, we don't
check device compatibility, and settings won't be shown due to a check
AuxiliarySearchControllerFactory#isEnabledAndDeviceCompatible(). In this
CL, we also check if the sharedPreference key has been set or not. If
not, we will continue to init the donor for device compatibility check.

Bug: 389520254
Change-Id: I9aa3502026fec995a592f9599a332f2f4870ab20
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6180426
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Auto-Submit: Xi Han <hanxi@chromium.org>
Commit-Queue: Xi Han <hanxi@chromium.org>
Reviewed-by: Gang Wu <gangwu@chromium.org>
Commit-Queue: Gang Wu <gangwu@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1408213}