Workflow with audio subjects should not be enabled for mobile

[mcbouslog]

Expected behavior

• if a workflow has a linked subject set with audio subjects then the workflow should not be enabled for mobile
• the mobile app does not support audio subjects

Current behavior

• a workflow with audio subjects that satisfies all other mobile requirements can be enabled for mobile

Steps to replicate

• staging project/workflow with audio subjects - https://master.pfe-preview.zooniverse.org/lab/1693/workflows/3333?env=staging

Notes

• update validations in https://github.com/zooniverse/Panoptes-Front-End/tree/master/app/pages/lab/mobile