Game Driver: Process sphal libraries in GraphicsEnvironment

Previously, there's only one Game Driver existed in the system, so we process
sphal libraries in GPU service to save the launch time for loading Game Driver.
Now we need to support a separate prerelease driver, so we have to move the
processing back to app launch time.

Bug: 134881329
Test: Manual test with prerelease driver and Settings UI.
Change-Id: Ic1bb412a6a026c68f55243c906bd56fe1fee44c3