In detection_stopped event, consider when no environmental sensors exist

In detection_stopped event, consider when no environmental sensors exist

1/ If there is no environmental sensor, send UAM_DETECTION_CYCLE_END only once.
2/ First update service->remaining_time, then start various detections.
3/ Environmental sensors may send detection_stopped before start_detection of
connectivity sensor, which results in multiple detection stopped events to CAPI
within a detection window.

Change-Id: I1c149fe8be8f3f86bf053ac8167df765948df72e
Signed-off-by: Lokesh <l.kasana@samsung.com>