[stable15] Do not calculate folder size for parent that also needs proper scan, fixes #3524

[backportbot-nextcloud]

backport of #14425

[faily-bot]

🤖 beep boop beep 🤖

Here are the logs for the failed build:

Status of 16870: failure

TESTS=acceptance, TESTS-ACCEPTANCE=users

• tests/acceptance/features/users.feature:137

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  Scenario: change email                                               # /drone/src/github.com/nextcloud/server/tests/acceptance/features/users.feature:137
    Given I act as Jane                                                # ActorContext::iActAs()
    And I am logged in as the admin                                    # LoginPageContext::iAmLoggedInAsTheAdmin()
    And I open the User settings                                       # SettingsMenuContext::iOpenTheUserSettings()
    And I see that the list of users contains the user user0           # UsersSettingsContext::iSeeThatTheListOfUsersContainsTheUser()
    And I see that the mailAddress of user0 is ""                      # UsersSettingsContext::iSeeThatTheFieldOfUserIs()
    When I set the mailAddress for user0 to "[email protected]"       # UsersSettingsContext::iSetTheFieldForUserTo()
    And I see that the mailAddress cell for user user0 is done loading # UsersSettingsContext::iSeeThatTheCellForUserIsDoneLoading()
    Then I see that the mailAddress of user0 is "[email protected]"   # UsersSettingsContext::iSeeThatTheFieldOfUserIs()
      Failed asserting that two strings are equal.
      --- Expected
      +++ Actual
      @@ @@
      -''
      +'[email protected]'