xattr command removed from the restarting script to avoid the macOS notification

[tomasstrba]

Task/Issue URL: https://app.asana.com/0/1201048563534612/1207945245157372/f

Description:
xattr command removed from the restarting script to avoid the macOS notification.

Steps to test this PR:

1. Change the build number and version number to lower numbers (Version.xcconfig, BuildNumber.xcconfig)
2. Change the implementation of configureUpdater() in UpdateController.swift

    private func configureUpdater() {
        // The default configuration of Sparkle updates is in Info.plist
        updater = SPUStandardUpdaterController(updaterDelegate: self, userDriverDelegate: self)
        shouldShowManualUpdateDialog = false

        if updater.updater.automaticallyDownloadsUpdates != areAutomaticUpdatesEnabled {
            updater.updater.automaticallyDownloadsUpdates = areAutomaticUpdatesEnabled
        }

#if DEBUG
//        updater.updater.automaticallyChecksForUpdates = false
//        updater.updater.automaticallyDownloadsUpdates = false
//        updater.updater.updateCheckInterval = 0
#endif

        checkForUpdateInBackground()
    }

3. Run the app
4. Wait until the app loads a new update
5. Use "Restart to Update" button (either in settings, right menu or Release Notes page)
6. Make sure the app is restarted and the new app session has higher version and build number (DuckDuckGo -> About DuckDuckGo)

Definition of Done:

• Does this PR satisfy our Definition of Done?

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Internal references:

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[tomasstrba]

Thank you, @afterxleep! 🙏