wp: fix pw_log_set usage

pw_log_set resets the log level of the logger to the Pipewire's current
level.  Here, it's instead expected that the level is retained, so call
pw_log_set_level first.

It used to be that pw_init set the log level based on PIPEWIRE_DEBUG
value, but this is now done only when using Pipewire's default logger.

lib/wp/wp.c

@@ -41,6 +41,7 @@ wp_init (WpInitFlags flags)
       g_snprintf (lvl_str, 2, "%d", wp_spa_log_get_instance ()->level);
       g_warn_if_fail (g_setenv ("PIPEWIRE_DEBUG", lvl_str, TRUE));
     }
+    pw_log_set_level (wp_spa_log_get_instance ()->level);
     pw_log_set (wp_spa_log_get_instance ());
   }