…attern selection popup when pattern is already open
This PR does two things. Most importantly, it fixes a segfault that can
be caused by opening a recent file with pattern sync enabled.
Secondly, it makes it so that the pattern selection popup does not
appear if you already have text in the pattern editor for a given
provider (due to CLI args, a project file, pattern sync, etc.). If you
open a file normally, that text field is empty and the popup will appear
so you can select a pre-made pattern like usual.
67efea6444