Fix DateTime issue restoring deleted webapp (#16308)

* Fix issue restoring deleted WebApp

Fixes [issue](#13245) that prevents restoring deleted WebApps if the host running the script uses a locale with a different date format than en-US.

* Update ChangeLog.md

Include changelog for Restore-AzDeletedWebApp DateTime fix

src/Websites/Websites/ChangeLog.md

@@ -18,6 +18,7 @@
         - Additional information about change #1
 -->
 ## Upcoming Release
+* Updated `Restore-AzDeletedWebApp` to fix issue that prevents the cmdlet from working on hosts with a locale is anything different from `en-US`
 
 ## Version 2.11.0
 * Fixed `Set-AzWebAppSlot` to support MinTlsVersion version update [#17663]

src/Websites/Websites/Cmdlets/BackupRestore/RestoreAzureDeletedWebApp.cs

@@ -163,7 +163,7 @@ private string GetDeletedSiteResourceId()
                     {
                         throw new Exception("Deleted app not found");
                     }
-                    DeletedSite lastDeleted = deletedSites.OrderBy(ds => DateTime.Parse(ds.DeletedTimestamp)).Last();
+                    DeletedSite lastDeleted = deletedSites.OrderBy(ds => DateTime.Parse(ds.DeletedTimestamp, new System.Globalization.CultureInfo("en-US"))).Last();
                     if (deletedSites.Count() > 1)
                     {
                         WriteWarning("Found multiple matching deleted apps. Restoring the most recently deleted app, deleted at " + lastDeleted.DeletedTimestamp);