Switch test mapping config from `presubmit` to `wm` group

Migrate libgui tests from default testmapping presubmit configurations.
Switching to `wm` group will allow tests to run on cf & hw targets for
both presubmit and postsubmit.

Test: presubmit
Fixes: 424854996
Flag: EXEMPT test mappings
Change-Id: I19ef3f84772e64397d8bee137223d59c9e731679