Get rid of legacy lifecycle methods

[NDungurothu]

Please refactor the code to avoid these warning:

Please update the following components: Experiment
Warning: componentWillMount has been renamed, and is not recommended for use. See https://fb.me/react-async-component-lifecycle-hooks for details.

• Move code from componentWillMount to componentDidMount (preferred in most cases) or the constructor.

Please update the following components: Treatment
Warning: componentWillMount has been renamed, and is not recommended for use. See https://fb.me/react-async-component-lifecycle-hooks for details.

• Move code from componentWillMount to componentDidMount (preferred in most cases) or the constructor.