[feature] Add logout button to sidebar (#48)

This one should probably be scrutinized a little more than my previous two.

For example, I don't know why I needed to do this: https://codeberg.org/prplecake/masto-fe-standalone/src/commit/1a1f48ceaa544650a8b8f50f8fa4e8c7cdc44c12/app/javascript/flavours/glitch/features/ui/index.jsx#L152

~~But, it appears to work.~~ It's live at https://masto-fe.compostintraining.club if you want to test it out.

~~Edit: it breaks stuff. Images don't load anymore...~~ Maybe that was just a network glitch...

Fixes #21.

Reviewed-on: https://codeberg.org/superseriousbusiness/masto-fe-standalone/pulls/48
Co-authored-by: prplecake <me@prplecake.com>
Co-committed-by: prplecake <me@prplecake.com>

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

@@ -149,7 +149,9 @@ class SwitchingColumnsArea extends PureComponent {
 
   componentDidUpdate (prevProps) {
     if (![this.props.location.pathname, '/'].includes(prevProps.location.pathname)) {
-      this.node.handleChildrenContentChange();
+      if (this.node && this.node.handleChildrenContentChange === 'function') {
+        this.node.handleChildrenContentChange();
+      }
     }
 
     if (prevProps.singleColumn !== this.props.singleColumn) {