{AzureCompute} Fix the OSDiskImage parameter in Example 6 for New-AzGalleryImageVersion cmdlet (#21410)

Fix the `OSDiskImage` parameter in Example 6 for `New-AzGalleryImageVersion` cmdlet

fixes #21400

Author: navba-MSFT

src/Compute/Compute/help/New-AzGalleryImageVersion.md

@@ -112,7 +112,7 @@ $galleryImageDefinitionName = "myImage"
 $galleryImageVersionName = "1.0.0"
 $location = "eastus"
 $osSnapshot = @{Source = @{Id = "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/mySnapshotRG/providers/Microsoft.Compute/snapshots/myOSSnapshot" }}
-New-AzGalleryImageVersion -ResourceGroupName $rgName -GalleryName $galleryName -GalleryImageDefinitionName $galleryImageDefinitionName -Name $galleryImageVersionName -Location $location -OSDiskImage $osDisk
+New-AzGalleryImageVersion -ResourceGroupName $rgName -GalleryName $galleryName -GalleryImageDefinitionName $galleryImageDefinitionName -Name $galleryImageVersionName -Location $location -OSDiskImage $osSnapshot
 ```
 
 Create an image version from a disk snapshot