ci: Also set bootstrap for MSYS shell in non-deps builds
This was missed in 96dc5ea4 and breaks all pipelines triggered by gstreamer merge requests, such as:
https://gitlab.freedesktop.org/nirbheek/gstreamer/-/pipelines/527877
Due to an influx of spam, we have had to impose restrictions on new accounts. Please see this wiki page for instructions on how to get full permissions. Sorry for the inconvenience.
This was missed in 96dc5ea4 and breaks all pipelines triggered by gstreamer merge requests, such as:
https://gitlab.freedesktop.org/nirbheek/gstreamer/-/pipelines/527877