Device Dehydration: "Set up recovery" does not set up dehydrated device

[richvdh]

STR:

1. Enable MSC3814 on synapse (experimental_features: msc2697_enabled: false msc3814_enabled: true)
2. Enable MSC3814 flag in well-known (extra_well_known_client_content: { "org.matrix.msc3814": true })
3. Log in on a fresh account
4. Settings -> Encryption -> Recovery -> Set up recovery
5. Jump through the hoops

The above process should enable device dehydration; however it does not.