Asset localization does not work properly for Paper2D related assets such as Flipbook

This issue is resolved by changing Paper2D's LoadingPhase to PostConfigInit, but this is a workaround. We suggest a better long term fix via AssetRegistry changes (see comments).

In the default language (probably the OS language), Paper2D assets will not be localized.

At the timing (FEnginePackageLocalizationCache :: FindLocalizedPackages) when the localization function extracts each asset path of L10N or less through AssetRegistry immediately after startup, the CustomVersion information of Paper2D was not loaded yet. Specifically, the GUID of CustomVersion of Paper2D is not registered in the Queue of FStaticCustomVersionRegistry of CustomVersion.cpp. 

1. play standalone with attached project
2. press 1 ( for change to jp )
3. press 3 ( for restart )
4. press 2 ( for change to en )
5. press 3 ( for restart )

expect : You can see the assets (rabbit picture) localized in 1 and 5.
result : You can see coin image in 1 and 5.