Simplify app prediction service check

In support of sharesheet unbundling:
This code directly accesses private platform config resources
and cannot be used outside of system_server.

This was originally added during the Q->R transition as app
prediction service was ramping up [See b/138595943].
Incorrect versions would cause increased latency in opening
the sharesheet, app prediction missing but no crash.

If there is a problem with AiAi version configuration, that
should be addressed directly and not covered over by silently
disabling functionality.

At this time the package name returned from the system call
PackageManager#getAppPredictionServicePackageName() is passed
through the function "ensureSystemPackage" before being
returned this is sufficient to satisfy and availability checks.

Bug: 220895016
Test: manual; share content from app, verify share targets
Change-Id: I11aebe4fba1d96b543ba89482313668ce55b8ca4