Windows get left behind when restoring programs for workspace that is not yet focused

[JonnyHaystack]

Describe the bug
Say you are on workspace 1 and you execute i3-resurrect restore -w 2 --programs-only, sometimes one or more program windows may get launched on workspace 1 instead of workspace 2.

I believe this is because the launching of programs with python's subprocess module is not synchronous with the workspace switching using i3.command(f'workspace --no-auto-back-and-forth {workspace}'). I'm experimenting right now using i3's exec command to launch programs instead and that seems to work, although unfortunately I have to do some slightly hacky things to make it work right..

To Reproduce
Described above.

Expected behavior
All programs should be launched on the workspace whose programs you are restoring.

System information (please complete the following information):

• Linux distribution: Arch Linux
• i3-resurrect version (output of i3-resurrect --version): 1.3.2
• i3 version (output of i3 -v): 4.17.1
• Python version (output of python -V): 3.7.4