Fix playlist duration display

Description

This MR updates the display of playlists specifically to address streaming media. Currently a pls file with four streams shows as "4 tracks · null+" not the expected "4 tracks". The change is to use the duration in a conditional to only append a duration if not equal to zero.

How Has This Been Tested?

Tested with XSPF and PLS files. Information shows as expected.

Screenshot

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist

• I have read the CONTRIBUTING section of the README document.