fix(server): DriveFile related N+1 query when call note packMany (#10133)

* fix(server): DriveFile related N+1 query when call note packMany

* Update packages/backend/src/misc/is-not-null.ts

Co-authored-by: Acid Chicken (硫酸鶏) <root@acid-chicken.com>

* ignore lint

* 途中でやめたやつが混入していた

* fix: 順番通りである必要がある場所で順番通りになっていなかった

---------

Co-authored-by: Acid Chicken (硫酸鶏) <root@acid-chicken.com>

packages/backend/src/misc/is-not-null.ts

@@ -0,0 +1,5 @@
+// we are using {} as "any non-nullish value" as expected
+// eslint-disable-next-line @typescript-eslint/ban-types
+export function isNotNull<T extends {}>(input: T | undefined | null): input is T {
+	return input != null;
+}