Lazy-fetch the settings for extensions (#38844)

This PR stops us from synchronously initializing the settings page for every extension (including built-in's) on startup. That incurs a small penalty that really adds up the more extensions a user has.

Instead, we'll now only initialize the `CommandSettings` object when we first actually need it. 

From a relatively unscientific test, this saves approximately 10% on the initialization of builtin commands, and for my setup, it trims about 28% off extension initialization (across all built-in's / extensions):

branch | Built-in load (ms) | Extension load (ms) | %Δ builtin | %Δ extensions | 
-- | -- | -- | -- | -- |
main | 1455 | 6867.6 | | |
this PR | 1309.2 | 4919 | -10.02% | -28.37%

Closes #38321

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/CommandProviderWrapper.cs

@@ -66,8 +66,10 @@ public sealed class CommandProviderWrapper
         DisplayName = provider.DisplayName;
         Icon = new(provider.Icon);
         Icon.InitializeProperties();
+
+        // Note: explicitly not InitializeProperties()ing the settings here. If
+        // we do that, then we'd regress GH #38321
         Settings = new(provider.Settings, this, _taskScheduler);
-        Settings.InitializeProperties();
 
         Logger.LogDebug($"Initialized command provider {ProviderId}");
     }
@@ -151,9 +153,11 @@ public sealed class CommandProviderWrapper
             Icon = new(model.Icon);
             Icon.InitializeProperties();
 
+            // Note: explicitly not InitializeProperties()ing the settings here. If
+            // we do that, then we'd regress GH #38321
             Settings = new(model.Settings, this, _taskScheduler);
-            Settings.InitializeProperties();
 
+            // We do need to explicitly initialize commands though
             InitializeCommands(commands, fallbacks, serviceProvider, pageContext);
 
             Logger.LogDebug($"Loaded commands from {DisplayName} ({ProviderId})");
@@ -194,21 +198,6 @@ public sealed class CommandProviderWrapper
         }
     }
 
-    /* This is a View/ExtensionHost piece
-     * public void AllowSetForeground(bool allow)
-    {
-        if (!IsExtension)
-        {
-            return;
-        }
-
-        var iextn = extensionWrapper?.GetExtensionObject();
-        unsafe
-        {
-            PInvoke.CoAllowSetForegroundWindow(iextn);
-        }
-    }*/
-
     public override bool Equals(object? obj) => obj is CommandProviderWrapper wrapper && isValid == wrapper.isValid;
 
     public override int GetHashCode() => _commandProvider.GetHashCode();