Import discord in the executor to avoid blocking the event loop (#111790)

`2024-02-28 19:20:04.485 DEBUG (MainThread) [homeassistant.loader] Component discord import took 1.181 seconds (loaded_executor=False)`

homeassistant/components/discord/manifest.json

@@ -4,6 +4,7 @@
   "codeowners": ["@tkdrob"],
   "config_flow": true,
   "documentation": "https://www.home-assistant.io/integrations/discord",
+  "import_executor": true,
   "integration_type": "service",
   "iot_class": "cloud_push",
   "loggers": ["discord"],