fix(backend): 起動前の疎通チェックが機能しなくなっていた問題を修正 (#15043)

* check harder for connectibility

`allSettled` does not throw if a promise is rejected, so
`check_connect` never actually failed

* Update Changelog

---------

Co-authored-by: dakkar <dakkar@thenautilus.net>

packages/backend/scripts/check_connect.js

@@ -53,4 +53,4 @@ const promises = Array
 		connectToPostgres()
 	]);
 
-await Promise.allSettled(promises);
+await Promise.all(promises);