Rechecks if the intent component specified

This is a regression issue by commit 54fbb053 where the value of
componentSpecified only rely on the caller while building the
ActivityStarter without checking the given intent. This could
resulted in wrong activity type (e.g home) while starting an
Activity.

Bug: 290583872
Test: atest ActivityStarterTests
Change-Id: Id9554466af819811006eb501873340ec94dc696b