pipewire: send timing reports earlier

The timing can now be sent just after pw is starting, the timing
audio_ts will very likely be VLC_TICK_0 (or first_pts).

This fixes video glitches on startup.

modules/audio_output/pipewire.c

@@ -194,8 +194,10 @@ static void stream_process(void *data)
             memset(dst, 0, skip);
             dst += skip;
             room -= skip;
-        } else if (s->time.pts != VLC_TICK_INVALID && now >= s->time.next_update
-                && s->first_pts != VLC_TICK_INVALID) {
+        }
+
+        if (!s->starting && s->time.pts != VLC_TICK_INVALID
+         && now >= s->time.next_update && s->first_pts != VLC_TICK_INVALID) {
             vlc_tick_t elapsed = now - s->time.pts;
             /* A sample injected now would be delayed by the following amount of vlc_tick_t */
             vlc_tick_t delay = vlc_tick_from_samples(s->time.frames, s->time.rate)