startActivityForResult with earlier new Intent

We already make sure to use a copy of the Intent, but now we do so
earlier. See bug.

Bug: 353680402
Flag: EXEMPT bugfix
Test: manual
Test: atest com.android.settings.users.UserSettingsTest
            com.android.settings.users.UserDetailsSettingsTest
Change-Id: I860e9e606de6b8d3c99fa52a63b72ba7a99ce179