Previously, the tracer pad-push-event was only signalled on
gst_pad_push_event(). However, the sticky event handling code in
GStreamer uses gst_pad_push_event_unchecked() instead, which meant those
events were not logged.
This patch extends the definition of the pad-push-event tracer to cover
both calls to gst_pad_push_event() and any direct calls to
gst_pad_push_event_unchecked() that skip the former inside GstPad
private code.
gst_pad_push_event_unchecked() returns GstFlowReturn instead of
gboolean like gst_pad_push_event(). To maintain API compatibility, the
GstFlowReturn is converted to gboolean.
Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/4182
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/8342>