Add FORGE_DISABLE_METRICS check when init_backend (meta-pytorch#440)

Author: DNXie

src/forge/observability/metric_actors.py

@@ -75,6 +75,7 @@ async def get_or_create_metric_logger(
     """
     # Get or create the singleton global logger
     global _global_logger
+
     if _global_logger is None:
         _global_logger = await get_or_spawn_controller(
             "global_logger", GlobalLoggingActor
@@ -203,6 +204,9 @@ async def init_backends(self, config: dict[str, Any]) -> None:
         """
         self.config = config
 
+        if FORGE_DISABLE_METRICS.get_value():
+            return
+
         for backend_name, backend_config in config.items():
             backend = get_logger_backend_class(backend_name)(backend_config)
             await backend.init(role=BackendRole.GLOBAL)