Revert "Make createSource(ContentResolver, Uri, Resources) a SystemApi"

Bug: 152322291
Bug: 172934376
Test: make

This reverts commit 97eacc36.

Reason for revert: The UI Rendering mainline module is on hold for
now, so this does not need to be @SystemApi. The system can still
access it through @hide.

Change-Id: I0f4d685d62cf468a3fd9a7e664bcc46569e94591