Un-revert IPlayerManager refactor (#21244)

Content.Shared/Players/PlayerDataExt.cs

@@ -0,0 +1,30 @@
+using Robust.Shared.Player;
+
+namespace Content.Shared.Players;
+
+public static class PlayerDataExt
+{
+    /// <summary>
+    ///     Gets the correctly cast instance of content player data from an engine player data storage.
+    /// </summary>
+    public static ContentPlayerData? ContentData(this SessionData data)
+    {
+        return (ContentPlayerData?) data.ContentDataUncast;
+    }
+
+    /// <summary>
+    ///     Gets the correctly cast instance of content player data from an engine player data storage.
+    /// </summary>
+    public static ContentPlayerData? ContentData(this ICommonSession session)
+    {
+        return session.Data.ContentData();
+    }
+
+    /// <summary>
+    ///     Gets the mind that is associated with this player.
+    /// </summary>
+    public static EntityUid? GetMind(this ICommonSession session)
+    {
+        return session.Data.ContentData()?.Mind;
+    }
+}