Fix Random unitttest failure (#40390)

The test
`Win32ProgramRepositoryMustCallOnAppRenamedForLnkAppsWhenRenamedEventIsRaised`
was experiencing random failures due to object identity mismatches in
the repository's hash-based storage system.

## Root Cause

The test was manually creating `Win32Program` objects:

```csharp
Win32Program olditem = new Win32Program
{
    Name = "oldpath",
    ExecutableName = oldpath,
    FullPath = linkingTo,
};
```

However, the `DoOnAppRenamedAsync` method creates the `oldApp` object
for removal using a different approach for .lnk files:

```csharp
oldApp = new Win32Program() { 
    Name = Path.GetFileNameWithoutExtension(e.OldName), 
    ExecutableName = Path.GetFileName(e.OldName), 
    FullPath = newApp?.FullPath ?? oldPath 
};
```

Since the repository uses `GetHashCode()` (based on `Name`,
`ExecutableName`, and `FullPath`) to identify objects for removal, any
subtle differences in these properties would cause the `Remove()`
operation to fail, leading to test assertion failures.

## Fix

Changed the test to use `Win32Program.GetAppFromPath()` instead of
manual object creation:

```csharp
Win32Program olditem = Win32Program.GetAppFromPath(oldFullPath);
Win32Program newitem = Win32Program.GetAppFromPath(newFullPath);
```

This mirrors the approach used in the working
`Win32ProgramRepositoryMustCallOnAppRenamedForUrlAppsWhenRenamedEventIsRaised`
test and ensures that test objects are created using the same code path
as the production code, eliminating hash code mismatches.

## Why This Was Random

The test failure appeared random because it depended on subtle
differences in object creation that could vary based on timing, mock
setup, or other environmental factors. By using the same object creation
method as the production code, the test becomes deterministic.

src/modules/launcher/Plugins/Microsoft.Plugin.Program.UnitTests/Storage/Win32ProgramRepositoryTest.cs

@@ -363,7 +363,7 @@ namespace Microsoft.Plugin.Program.UnitTests.Storage
             RenamedEventArgs e = new RenamedEventArgs(WatcherChangeTypes.Renamed, directory, path, oldpath);
 
             string oldFullPath = directory + "\\" + oldpath;
-            string fullPath = directory + "\\" + path;
+            string newFullPath = directory + "\\" + path;
             string linkingTo = Directory.GetCurrentDirectory();
 
             // ShellLinkHelper must be mocked for lnk applications
@@ -372,19 +372,8 @@ namespace Microsoft.Plugin.Program.UnitTests.Storage
             Win32Program.ShellLinkHelper = mockShellLink.Object;
 
             // old item and new item are the actual items when they are in existence
-            Win32Program olditem = new Win32Program
-            {
-                Name = "oldpath",
-                ExecutableName = oldpath,
-                FullPath = linkingTo,
-            };
-
-            Win32Program newitem = new Win32Program
-            {
-                Name = "path",
-                ExecutableName = path,
-                FullPath = linkingTo,
-            };
+            Win32Program olditem = Win32Program.GetAppFromPath(oldFullPath);
+            Win32Program newitem = Win32Program.GetAppFromPath(newFullPath);
 
             win32ProgramRepository.Add(olditem);