`useResizeHandler` does not respond to container layout changes

Currently, useResizeHandler only responds to window.resize events.

This works when the browser viewport changes, but it does not cover layout changes that resize the plot without resizing the window.

For example, if a page contains a collapsible sidebar and a responsive plot in the same page, toggling the sidebar changes the space available to the plot, but no window.resize event is fired. The plot therefore keeps its previous size until Plotly.Plots.resize() is called manually.

Would it make sense for useResizeHandler to react to changes in the rendered plot element's size instead of only listening to window.resize?

One possible approach would be to use ResizeObserver when available, while keeping the existing window.resize listener as a fallback.

Inizia dall’implementazione di useResizeHandler e traccia il modo in cui attualmente si sottoscrive a window.resize. Controlla i test esistenti relativi alla gestione del ridimensionamento, quindi verifica che le modifiche all’elemento del plot renderizzato attivino il ridimensionamento, mentre il fallback di window.resize continui a funzionare. Il lavoro è completo quando le modifiche a un layout comprimibile ridimensionano il plot senza una chiamata manuale a Plotly.Plots.resize().