Stop loading other package's font by default.

Since CONTEXT_RESTRICTED is not a default flag of createPackageContext,
we can't rely on it for preventing unexpected font injections.
To protect developers and existing apps from a risk of font injection,
stop loading font from other package's resouce unless the developer
explicitly set CONTEXT_IGNORE_SECURITY.

Bug: 62813533
Bug: 62879353
Test: Manually done
Change-Id: I4442ddc48dadb5c968b444be86038b602074d301