Enable deletion of integration resources (#1294)

* Enforce admin service user role for integration group deletion

Added a check to prevent non-admin service users from deleting integration groups.

* Restrict deletion of integration user to admin service user only

* Refactor user and group deletion tests

management/server/user_test.go

@@ -508,7 +508,7 @@ func TestUser_DeleteUser_regularUser(t *testing.T) {
 			name:             "Delete integration regular user permission denied ",
 			userID:           "user4",
 			assertErrFunc:    assert.Error,
-			assertErrMessage: "only integration can delete this user",
+			assertErrMessage: "only admin service user can delete this user",
 		},
 	}