Investigate replacing setTimeout for rendering/displaying components with animation

## Summary
Investigate other methods to conditionally render/display components which are initially hidden and which require animation when they are rendered/displayed.

## 💬 Description
We currently add animation to components which are initially hidden but which require animation when they are rendered/displayed using the setTimeout method. While this does seem to be a common method in the wider industry it is worth investigating whether there are other, potentially cleaner, methods of achieving this same functionality, e.g. event listeners that trigger when the component has been set to display and add the animation class.

## 💰 Use value
Potentially improve the overall quality of our code, otherwise validate our current solution.

## Additional info

Start by locating the components that use setTimeout for initially hidden content and inspect how their rendering, display state, and animation classes interact. Compare the current approach with event-listener or other alternatives, then document whether a cleaner replacement is justified or validate the existing solution.

Written by the indexing model from the issue text.