s13n: Remove unnecessary signin-related includes in local_card_migration_browsertest.cc

There is no use of SigninFoo class in local_card_migration_browsertest.cc. So they are
unnecessary now. This CL removes the includes.

Bug: 927244
Change-Id: If20a6806a63123165a865e83c3cf86188b71f2bd
Reviewed-on: https://chromium-review.googlesource.com/c/1448010Reviewed-by: Evan Stade <estade@chromium.org>
Commit-Queue: Gyuyoung Kim <gyuyoung@igalia.com>
Cr-Commit-Position: refs/heads/master@{#628518}

chrome/browser/ui/views/autofill/local_card_migration_browsertest.cc

@@ -15,11 +15,7 @@
 #include "base/test/scoped_feature_list.h"
 #include "chrome/browser/autofill/autofill_uitest_util.h"
 #include "chrome/browser/signin/account_fetcher_service_factory.h"
-#include "chrome/browser/signin/account_tracker_service_factory.h"
-#include "chrome/browser/signin/fake_account_fetcher_service_builder.h"
-#include "chrome/browser/signin/fake_signin_manager_builder.h"
 #include "chrome/browser/signin/identity_manager_factory.h"
-#include "chrome/browser/signin/signin_manager_factory.h"
 #include "chrome/browser/sync/profile_sync_service_factory.h"
 #include "chrome/browser/sync/test/integration/profile_sync_service_harness.h"
 #include "chrome/browser/sync/test/integration/sync_test.h"