Don't allow app handle to be drawn for any task w/ default home package.

If there's a task that's of the default home launcher package, let's not
draw the app handle. Although we have ACTIVITY_HOME to guard against
general launcher activity already, there are other activities (e.g.
ProxyActivityStarter) in the package that we don't want to enter
freeform.

Bug: 365023423
Test: no longer seeing app handle when launching widget settings
Flag: EXEMPT bugfix
Change-Id: I33ab6f3d4198d3c531d4323712ae8bdc2672de01