Update Remove-SPOSiteDesign.md

Correction: -Identity is required parameter.

Author: aaronmi

sharepoint/sharepoint-ps/sharepoint-online/Remove-SPOSiteDesign.md

@@ -44,7 +44,7 @@ Type: SPOSiteDesignPipeBind
 Parameter Sets: (All)
 Aliases: 
 Applicable: SharePoint Online
-Required: False 
+Required: True 
 Position: Named
 Default value: None
 Accept pipeline input: False