Remove kati marker in soong-only build

Previously we ensured the kati marker exists in kati-enabled builds, but
did not ensure the kati marker didn't exist in non-kati-enabled builds,
resulting in soong thinking kati would run after it when it would not.

Also change the condition to only create the kati_enabled marker if we
don't skip kati or kati ninja.

Bug: 189187214
Test: m nothing && soong_ui --make-mode --soong-only && verify
      kati_enabled marker is gone
Change-Id: If196b194b6aee38e9d4135889a4a4048ee5add82