Use mock dependency LocalBluetoothManager

A *real* LocalBluetoothManager was being used in the tests and
registering (and not unregistering) multiple broadcast receivers which
was causing the systemui.tests package to exceed its limit for
registered receivers.

Test: atest SystemUITests
Bug: 151614195
Change-Id: I6976abf8ea4f3e984be7aa5393dd7aac5a3ee509