Controls UI - Add 'reset' option for seeding

Enable for testing controls seeding. Make sure subscriptions are
cleaned up properly. Up the seeding limit to 6. If we received our
requested control limit on load, cancel() the subscription and
immediately load.

Bug: 153455870
Test: manual, use 'Reset' button to test seeding process

Change-Id: I536315de423c49231e77c0b1b24ad20883ddaae7