Element iOS sends wrong format to /keys/query

[neilalexander]

The /keys/query request contains the wrong format. The spec calls for device_keys to take the format {string: [string]} but Element iOS is sending {string: {string: bool, string: bool, ...}}.

Synapse ignores this because it doesn't check the type and processes it as an array (possibly incorrectly, not sure). Dendrite raises an error because we are strict about the type.