Move saas-related initialization to a startup hook.

Previously, the saas-related initialization was not taking effect for the general
webapp runtime - the saas registry would need to be reloaded from disk on the first
API invocation, which added unneeded overhead to that first API call.
With this change, the registry loading from disk is done on server initialization
and is not needed again.

src/fidesops/main.py

@@ -100,6 +100,20 @@ async def dispatch_log_request(request: Request, call_next: Callable) -> Respons
         raise
 
 
+@app.on_event("startup")
+async def load_saas_registry():
+    """
+    Load the SaaS registry on a startup hook to get the registry initialized
+    within the app's runtime
+    """
+    if config.database.enabled:
+        logger.info("Validating SaaS connector templates...")
+        registry = load_registry(registry_file)
+        db = get_api_session()
+        update_saas_configs(registry, db)
+        db.close()
+
+
 async def prepare_and_log_request(
     endpoint: str,
     hostname: Optional[str],
@@ -237,16 +251,10 @@ def start_webserver() -> None:
         )
         config.log_all_config_values()
 
-    logger.info("Validating SaaS connector templates...")
-    registry = load_registry(registry_file)
-
     if config.database.enabled:
         logger.info("Running any pending DB migrations...")
         try:
             init_db(config.database.sqlalchemy_database_uri)
-            db = get_api_session()
-            update_saas_configs(registry, db)
-            db.close()
         except Exception as error:  # pylint: disable=broad-except
             logger.error("Connection to database failed: %s", Pii(str(error)))
             return