Revert interpolated string use in Get-Object so previous formatting behavior is preserved

Author: SteveL-MSFT

src/Microsoft.PowerShell.Commands.Utility/commands/utility/Group-Object.cs

@@ -153,15 +153,15 @@ private static string BuildName(List<ObjectCommandPropertyValue> propValues)
 
                         foreach (object item in propertyValueItems)
                         {
-                            sb.Append(CultureInfo.InvariantCulture, $"{item}, ");
+                            sb.AppendFormat(CultureInfo.InvariantCulture, "{0}, ", item.ToString());
                         }
 
                         sb = sb.Length > length ? sb.Remove(sb.Length - 2, 2) : sb;
                         sb.Append("}, ");
                     }
                     else
                     {
-                        sb.Append(CultureInfo.InvariantCulture, $"{propValuePropertyValue}, ");
+                        sb.AppendFormat(CultureInfo.InvariantCulture, "{0}, ", propValuePropertyValue.ToString());
                     }
                 }
             }