[passwords/desktop] Remove default PasswordStore pref

More context in the doc of the linked bug. Migrates users that
had the default store explicitly set to "profile store" to be opted
out of account storage instead. Users who configured this in the past
and signed out since are also migrated, since account storage settings
are supposed to survive sign-out.
And with that, the CL also (finally) deprecates
password_manager::prefs::kAccountStoragePerAccountSettings, a work
that was started with crrev.com/c/4874142 and crrev.com/c/5072932.

OBSOLETE_HISTOGRAMS=The states kSignedInAccountStoreUserSavingLocally and kSignedInUserSavingLocally were deleted, along with their metrics.

Bug: 369341336
Change-Id: Ie79e4d0f6e2495b23c620253d158f5b546598096
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5886669
Code-Coverage: [email protected] <[email protected]>
Reviewed-by: Mohamed Amir Yosef <[email protected]>
Commit-Queue: Victor Vianna <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1408934}
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index c3f3790..97a0578 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -2887,6 +2887,12 @@
   // Added 12/2024.
   profile_prefs->ClearPref(kPageContentCollectionEnabled);
 
+#if !BUILDFLAG(IS_ANDROID)
+  // Added 01/2025.
+  password_manager::features_util::MigrateDefaultProfileStorePref(
+      profile_prefs);
+#endif  // !BUILDFLAG(IS_ANDROID)
+
   // Added 01/2025.
   profile_prefs->ClearPref(kCompactModeEnabled);