Send intent for UI when providers are updated

Adds an intent that can be consumed by the UI app
with the list of current providers as an extra. The
intent is limited to the UI app component so this
won't be picked up by other apps.

Test: make & run on device
Bug: 253157366
Change-Id: I01fe9286eeb37f076af0fd0bf0d59659d92f5bab