CmdPal: Update Extension SDK classes to raise property change notifications only on change (#44547)

## Summary of the Pull Request

This PR introduces a new method  
`bool SetProperty<T>(ref T field, T value, [CallerMemberName] string?
propertyName = null)`
on `BaseObservable`.

The method updates the backing field only when the new value differs
from the current one and raises property change notifications only in
that case.

#### Summary

- Adds `SetProperty<T>` to `BaseObservable` to guard property change
notifications behind an actual value change.
- SDK API is not affected.
- Prevents unnecessary notifications from leaving the extension
boundary.
- Reduces redundant updates and saves a few round-trips between COM
objects and view models.
- Improves overall efficiency without changing observable behavior for
consumers.

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## PR Checklist

- [ ] Closes: #xxx
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issues) -->
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
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pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
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pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

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## Detailed Description of the Pull Request / Additional comments

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## Validation Steps Performed

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/Details.cs

@@ -7,65 +7,15 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class Details : BaseObservable, IDetails, IExtendedAttributesProvider
 {
-    public virtual IIconInfo HeroImage
-    {
-        get => field;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(HeroImage));
-        }
-    }
+    public virtual IIconInfo HeroImage { get; set => SetProperty(ref field, value); } = new IconInfo();
 
-= new IconInfo();
+    public virtual string Title { get; set => SetProperty(ref field, value); } = string.Empty;
 
-    public virtual string Title
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Title));
-        }
-    }
+    public virtual string Body { get; set => SetProperty(ref field, value); } = string.Empty;
 
-= string.Empty;
+    public virtual IDetailsElement[] Metadata { get; set => SetProperty(ref field, value); } = [];
 
-    public virtual string Body
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Body));
-        }
-    }
-
-= string.Empty;
-
-    public virtual IDetailsElement[] Metadata
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Metadata));
-        }
-    }
-
-= [];
-
-    public virtual ContentSize Size
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Size));
-        }
-    }
-
-= ContentSize.Small;
+    public virtual ContentSize Size { get; set => SetProperty(ref field, value); } = ContentSize.Small;
 
     public IDictionary<string, object>? GetProperties() => new ValueSet()
     {