fix #3958

[knighthat]

Old algorithm

if (songs.size > maxSongsInQueue.number) 
    songs.shuffled().take(maxSongsInQueue.number.toInt())
else
    songs

Shuffle only happens when number of songs is larger than the queue allows.

New algorithm

songs.shuffled().take( maxSongsInQueue )

Shuffle regardless. Besides, List#take will take up to specified number, if list's size is smaller, it'll return all elements, no need to check