11865: Fix: Select correct insert position for disabled group import r=jonasbb a=jonasbb
The logic for importing with and without `group_imports` differed
significantly when no previous group existed. This lead to the problem
of using the wrong position when importing inside a module (#11585) or
when inner attributes are involved.
The existing code for grouped imports is better and takes these things
This PR changes the flow to use the pre-existing code for adding a new
import group even for the non-grouped import settings.
Some coverage markers are updated and the `group` is removed, since they
are now invoked in both cases (grouping and no grouping).
Tests are updated and two tests (empty module and inner attribute) are
Co-authored-by: Jonas Bushart <firstname.lastname@example.org>