fix: 添付ファイルのあるリクエストを受けたときの初動を改善 (#15896)

* wip

* ロールポリシーの値も参照するように

* エンドポイントのテストを追加

* fix review

* add spdx

* fix CHANGELOG.md

* fix test

* regenerate

* add log

* Revert "add log"

This reverts commit 4b2bf59a60.

* add log

* fix

* Revert "add log"

This reverts commit c5a73d57da.

packages/backend/package.json

@@ -222,6 +222,7 @@
 		"@types/semver": "7.7.0",
 		"@types/simple-oauth2": "5.0.7",
 		"@types/sinonjs__fake-timers": "8.1.5",
+		"@types/supertest": "6.0.3",
 		"@types/tinycolor2": "1.4.6",
 		"@types/tmp": "0.2.6",
 		"@types/vary": "1.1.3",
@@ -238,6 +239,7 @@
 		"jest-mock": "29.7.0",
 		"nodemon": "3.1.10",
 		"pid-port": "1.0.2",
-		"simple-oauth2": "5.1.0"
+		"simple-oauth2": "5.1.0",
+		"supertest": "7.1.0"
 	}
 }