Bug: Changing file permission for multiple files simultaneously crashes app

[jh961202]

Description

When setting permission ( readonly, etc. ) with Files' built-in properties dialog, Files will crash and exit after clicking OK button to apply settings.
This only happens when multiple items were chosen ( >= 2 items ), but no problems when dealing with single one item.

However, permissions of selected items will still be set properly even though Files crashes.

Steps To Reproduce

1. Go to any path that contains multiple items.
2. Select multiple items ( >=2 items ), and click "Properties" on the menu bar or context menu to bring out properties dialog
3. Modify any kind of permission ( noo matter the type ) and click OK.
4. See the error

Steps to fix

Looks like this is a standalone issue, no prerequisites should be accomplished before dealing with this one.
Log file is able to collect relevant error ( see the following )

Files Version

Version： 2.4.8.0 OS Version: 10.0.22621.963

Windows Version

Windows 11 22H2 22621.963

Relevant Assets/Logs

2022-12-29 10:48:46.8620|INFO|CheckForUpdates|STORE: Checking for updates...
2022-12-29 10:48:48.2666|INFO|IsRunningOnArm|Running on ARM: False
2022-12-29 10:49:10.3062|ERROR|AppUnhandledException|Object reference not set to an instance of an object.
System.NullReferenceException: Object reference not set to an instance of an object.
at Files.App.Views.PropertiesGeneral.SaveChangesAsync(ListedItem item)
at Files.App.Views.Properties.OKButton_Click(Object sender, RoutedEventArgs e)
at System.Threading.Tasks.Task.<>c.b__128_0(Object state)
at Microsoft.UI.Dispatching.DispatcherQueueSynchronizationContext.<>c__DisplayClass2_0.b__0()
--- End of stack trace from previous location ---
at WinRT.ExceptionHelpers.g__Throw|20_0(Int32 hr)
at ABI.Windows.ApplicationModel.Core.IUnhandledErrorMethods.Propagate(IObjectReference _obj)
at Microsoft.AppCenter.Utils.ApplicationLifecycleHelperWinUI.<.ctor>b__0_3(Object sender, UnhandledErrorDetectedEventArgs eventArgs)
--- End of stack trace from previous location ---
at Microsoft.AppCenter.Utils.ApplicationLifecycleHelperWinUI.<.ctor>b__0_3(Object sender, UnhandledErrorDetectedEventArgs eventArgs)
at ABI.System.EventHandler`1.Do_Abi_Invoke[TAbi](Void* thisPtr, IntPtr sender, TAbi args)

[hecksmosis]

Can confirm this is an issue

[hecksmosis]

I'll look into it

[hecksmosis]

@yaira2 can you approve this? (I've already resolved it)