ges-launcher: do not set rendering details too early

It looks like the _set_rendering_details call is superfluous
in _startup(), as it will get called in run_pipeline.

The problem with calling it before timeline_set_user_options
is that we are going to fail creating a smart profile if
the user selected eg --track-types=video, as the get_smart_profile
method compares the tracks in the asset with those on the timeline.

Reproduce with a video-only clip:

ges-launch-1.0 --track-types=video +clip file://$PWD/jelly.mp4 \
inpoint=15.0 -o foo.mp4 --smart-rendering

Part-of: <gstreamer/gst-editing-services!228>
32 jobs for !228 with fix-rendering-details in 42 minutes and 42 seconds (queued for 3 seconds)
detached
Status Job ID Name Coverage
  Build Docker
passed #7017728
alpine amd64 manifest builder docker

00:00:28

passed #7017727
android docker

00:00:22

passed #7017726
cerbero fedora amd64 docker

00:00:22

passed #7017725
fedora amd64 docker

00:00:23

passed #7017729
gst-indent amd64 docker

00:00:23

 
  Preparation
passed #7017732
check allow-edit

00:00:10

passed #7017731
gst indent

00:00:10

passed #7017730
manifest

00:00:33

 
  Build
passed #7017741
gstreamer
build cerbero cross-android universal

00:10:34

passed #7017745
gst-ios-14.3
build cerbero cross-ios universal

00:24:30

passed #7017742
gstreamer
build cerbero cross win32

00:07:14

passed #7017743
gstreamer
build cerbero cross win64

00:07:15

passed #7017740
gstreamer
build cerbero fedora x86_64

00:07:19

passed #7017744
gst-macos-11.1
build cerbero macos x86_64

00:13:59

passed #7017746
docker windows 1809 gstreamer-windows
build cerbero msvc x86_64

00:11:50

passed #7017736
build clang fedora x86_64

00:09:18

manual #7017739
docker windows 1809 allowed to fail manual
build msys2
passed #7017733
build nodebug fedora x86_64

00:05:20

passed #7017734
build static fedora x86_64

00:07:50

passed #7017735
build static nodebug fedora x86_64

00:04:41

passed #7017737
docker windows 1809
build vs2017 amd64

00:09:28

passed #7017738
docker windows 1809
build vs2017 x86

00:09:43

 
  Test
passed #7017747
gstreamer
check fedora

00:06:07

passed #7017748
gstreamer
integration testsuites fedora 1/4

00:14:39

passed #7017749
gstreamer
integration testsuites fedora 2/4

00:19:51

passed #7017750
gstreamer
integration testsuites fedora 3/4

00:13:48

passed #7018637
gstreamer
integration testsuites fedora 4/4

00:12:48

passed #7017752
gstreamer
valgrind ges

00:06:09

failed #7017751
gstreamer
integration testsuites fedora 4/4

00:17:33

 
  Integrate
passed #7017753
cross-android universal examples

00:08:26

passed #7017755
gst-ios-14.3
cross-ios universal examples

00:04:16

passed #7017754
documentation

00:13:42