net/aws/transcriber: fix eos not being sent

For eos to be sent from the srcpad task loop, we need to go through `dequeue`.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/1122>

net/aws/src/transcriber/imp.rs

@@ -536,7 +536,6 @@ impl Transcriber {
                     if notif.is_none() {
                         // Transcriber loop terminated
                         self.state.lock().unwrap().send_eos = true;
-                        return;
                     };
                 }
                 _ = timeout => (),