Media: Specify the duration during the insertion

We already know it, so we won't need a later update. This fixes an
issue where a video media without a title wouldn't get
save()'d, causing the duration to be silently dropped.
4 jobs for create_media_with_durations in 11 minutes and 9 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #281314
amd64 debian
asan-ubsan

00:11:07

passed #281311
amd64 debian
linux

00:08:59

passed #281312
win32
win32

00:11:00

passed #281313
win64
win64

00:09:57