ddev config --omit-containers="" doesn't remove omit_containers

[rfay]

Expected Behavior

ddev config --omit-containers="" doesn't remove the omit_containers config as you'd expect.

Probably the ddev config global doesn't either.

We need a way to remove this type of config.

If you ddev config --omit-containers=db and then ddev config --omit-containers="" the omit_containers[db] remains in .ddev/config.yaml