There is a context: state / net / "wifi connected"
So you have at least two choices:
1 - Add that wifi-connected context to all your autovoice profiles and trust that Tasker will use the good judgement to not monitor the high-power autovoice context when the low-power wifi-connected status is not satisfied (according to the documentaiton, Tasker doesn't monitor high-power contexts unless the lower power contexts are satisfied, but it's not 100% clear if that will extend to contexts created with plugins, like autovoice).
2- Create a separate profile with only the single context wifi-connected. Enter task is to enable all the relevant autovoice profiles (action: tasker / profile status / enable). Exit task is to disable all the relevant autovoice profiles.