camerabin: Fix source updates with user filters
Take the case into account when user filters have been set before the source gets updated.
Note that the further linking of the filters, if present, happens below
in the gst_camera_bin_check_and_replace_filter()
calls.
The audio filter is still affected by the same issue but left out for now.
Needed for https://gitlab.gnome.org/GNOME/snapshot/-/merge_requests/172 thus, once landed, a backport to 1.22 would be great :)
Edited by Robert Mader