[Glitch] Enable ESLint react/no-deprecated

Port b878e3d8df to glitch-soc

Signed-off-by: Claire <claire.github-309c@sitedethib.com>

app/javascript/flavours/glitch/features/ui/index.jsx

@@ -133,7 +133,7 @@ class SwitchingColumnsArea extends React.PureComponent {
     mobile: PropTypes.bool,
   };
 
-  componentWillMount () {
+  UNSAFE_componentWillMount () {
     if (this.props.mobile) {
       document.body.classList.toggle('layout-single-column', true);
       document.body.classList.toggle('layout-multiple-columns', false);
@@ -438,7 +438,7 @@ class UI extends React.Component {
     }
   }
 
-  componentWillReceiveProps (nextProps) {
+  UNSAFE_componentWillReceiveProps (nextProps) {
     if (nextProps.layout_local_setting !== this.props.layout_local_setting) {
       const layout = layoutFromWindow(nextProps.layout_local_setting);