Include widget providers enabled at runtime

The call to queryIntentReceivers only contains receivers that are
enabled. It does not return disabled receivers, whether disabled by
default and unmodified or disabled at runtime.

Therefore, the isEnabled check only has the effect of filtering out enabled widgets that were initially disabled in the manifest.

I have verified this locally with all 8 permutations of manifest-runtime
component enabled states.

Fix: 189087746
Test: locally, AppWidgetServiceImplTest
Change-Id: Ibc35005f8af31622134edb174469b39895b88ecc