Silence React error about getDerivedStateFromProps (#29544)

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/components/structures/RightPanel.tsx

@@ -64,6 +64,12 @@ export default class RightPanel extends React.Component<Props, IState> {
     public static contextType = MatrixClientContext;
     declare public context: React.ContextType<typeof MatrixClientContext>;
 
+    public constructor(props: Props) {
+        super(props);
+
+        this.state = RightPanel.getDerivedStateFromProps(props);
+    }
+
     private readonly delayedUpdate = throttle(
         (): void => {
             this.forceUpdate();