frontends (tools/webrtc): Fix audio muting.

libervia/frontends/tools/webrtc.py

@@ -632,7 +632,7 @@ class WebRTC:
             gst_pipe_elements.append(
                 f"""
         {audio_source_elt} name=audio_src
-        ! valve
+        ! valve name=audio_valve
         ! queue max-size-buffers=10 max-size-time=0 max-size-bytes=0 leaky=downstream
         ! audioconvert
         ! audioresample
@@ -1390,7 +1390,9 @@ class WebRTC:
 
         @param muted: True if audio is muted.
         """
-        if self.audio_valve is not None:
+        if self.audio_valve is None:
+            log.warning("No audio valve, can't mute.)")
+        else:
             self.audio_valve.set_property("drop", muted)
             state = "muted" if muted else "unmuted"
             log.info(f"audio is now {state}")