CreateRoomDialog is rendered before get default_federate value
CreateRoomDialog is rendered before get default_federate value

In React the order of the execution of mount and render functions
is: `componentWillMount --> render --> componentDidMount`

The `CreateRoomDialog` `render()` function is executed before than
the `componentDidMount()` function so the

  `this.defaultNoFederate = config.default_federate === false;`

; instruction which is executed in the `componentDidMount` function
(in `CreateRoomDialog`) is evaluated always after than the rendering
of the page.

Therefore, the obvious issue is that the values obtained from the
`SdkConfig.get()` function (`config.default_federate`) are obtained
later than their usage on `render()`.

This patch makes this change to fix the described issue:

* componentWillMount instead of componentDidMount

Signed-off-by: Pablo Saavedra <e98b8d93fe1b09b22b237dde7b57addaff055123@igalia.com>

matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk