[Android] Clean up ClearLoginDatabaseForAllMigratedUPMUsers flag

Chromium change:
https://chromium.googlesource.com/chromium/src/+/2bd4e38dc9ed39d922061a54b06d586528f33f7e

[UPMLoginDbSunset] Clean up ClearLoginDatabaseForAllMigratedUPMUsers

.. after launch. This was enabled by default in crrev.com/c/5975566.

Bug: 381113374

browser/password_manager/android/brave_password_manager_android_util_unittest.cc

@@ -86,9 +86,6 @@ class BravePasswordManagerAndroidUtilTest : public testing::Test {
 // We don't migrate and don't delete passwords DB.
 TEST_F(BravePasswordManagerAndroidUtilTest,
        SetUsesSplitStoresAndUPMForLocal_DeletesLoginDataFilesForMigratedUsers) {
-  base::test::ScopedFeatureList feature_list(
-      password_manager::features::kClearLoginDatabaseForAllMigratedUPMUsers);
-
   // This is a state of a local user that has just been migrated.
   pref_service()->SetInteger(kPasswordsUseUPMLocalAndSeparateStores,
                              base::to_underlying(kOn));