pulse: fix discovery of newly added devices
pulse: fix discovery of newly added devices

Fix regression introduced in 7bc5e28d85992b03e5852879b8d4d96043496caf
preventing the device provider to send the device-added message for new
devices.
By early returning the patch was discarding add/remove events.

Fix #735

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/-/merge_requests/626>

pexip/gst-plugins-good,pexip/gst-plugins-good,GStreamer/gst-plugins-good,pexip/gst-plugins-good,pexip/gst-plugins-good,GStreamer/gst-plugins-good,GStreamer/gst-plugins-good,GStreamer/gst-plugins-good,pexip/gst-plugins-good