fix some leaks

Make pw_get_client_name() return a static string.
Unload the dbus interface. Rename the method to make it more obvious
that the interface needs to be unloaded.
Free module properties
Free remote objects and types
Free stream params and the array

src/gst/gstpipewiresrc.c

@@ -319,7 +319,7 @@ gst_pipewire_src_init (GstPipeWireSrc * src)
 
   g_queue_init (&src->queue);
 
-  src->client_name = pw_get_client_name ();
+  src->client_name = g_strdup(pw_get_client_name ());
 
   src->pool =  gst_pipewire_pool_new ();
   src->loop = pw_loop_new (NULL);