Add missing icons to fitness/sky.yaml

This is just fallout from not having
https://github.com/domokit/sky_engine/issues/565

@abarth

Author: eseidelGoogle

examples/fitness/sky.yaml

@@ -2,9 +2,11 @@ material-design-icons:
   - name: action/assessment
   - name: action/help
   - name: action/settings
+  - name: action/view_list
+  - name: av/stop
   - name: content/add
   - name: maps/directions_run
   - name: navigation/arrow_back
+  - name: navigation/close
   - name: navigation/menu
   - name: navigation/more_vert
-  - name: av/stop