Remove "hours" digits if file is shorter than 1 hour

[TheCraigHewitt]

When a file is uploaded to Catsos via SSP, it returns the file duration in a format like this: 00:31:25 - it formats it like that even if the duration is less than 1 hour. For a site where all episodes are less than 1 hour, the "00" at the start of that string is very unnecessary and doesn't look great.