fix: restore os name in GetPublicSystemInfo endpoint

This is still used by clients to show platform-specific hardware acceleration options, restore the os name for now.

Signed-off-by: gnattu <gnattuoc@me.com>

Emby.Server.Implementations/SystemManager.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Linq;
 using System.Threading.Tasks;
 using MediaBrowser.Common.Configuration;
@@ -78,6 +79,7 @@ public class SystemManager : ISystemManager
         {
             Version = _applicationHost.ApplicationVersionString,
             ProductName = _applicationHost.Name,
+            OperatingSystem = GetServerOs(),
             Id = _applicationHost.SystemId,
             ServerName = _applicationHost.FriendlyName,
             LocalAddress = _applicationHost.GetSmartApiUrl(request),
@@ -100,4 +102,24 @@ public class SystemManager : ISystemManager
             _applicationLifetime.StopApplication();
         });
     }
+
+    private static string GetServerOs()
+    {
+        if (OperatingSystem.IsLinux())
+        {
+            return "Linux";
+        }
+
+        if (OperatingSystem.IsWindows())
+        {
+            return "Windows";
+        }
+
+        if (OperatingSystem.IsMacOS())
+        {
+            return "macOS";
+        }
+
+        return "Others";
+    }
 }

MediaBrowser.Model/System/PublicSystemInfo.cs

@@ -34,7 +34,6 @@ namespace MediaBrowser.Model.System
         /// Gets or sets the operating system.
         /// </summary>
         /// <value>The operating system.</value>
-        [Obsolete("This is no longer set")]
         public string OperatingSystem { get; set; } = string.Empty;
 
         /// <summary>