fix: fix "load" actions in dynamically added components

[ncoden]

Cleaner versions of #10947 - fix: support dynamically added components (@DanielRuf)

Prevent bugs in Accordion, Magellan, OffCanvas, Reveal, Sticky, Tabs and trigger utilities when the component is dynamically added because the window load event they rely on would never be triggered.

Changes:

• add onLoad utility to wait for window load even after it is already loaded
• fix various component listeners on window load when the window is already loaded

Notes:

• In addition to the bug fix, Accordion now smoothly scroll to the opened pane when the hash is changed
• When a Magellan component is dynamically created, the window DO NOT scroll to the target corresponding to the location hash as the magellan did not created the target and should appear without effects on it after the page already loaded.

[DanielRuf]

This should be fn(); as setTimeout creates a new context and does not bind _this and nother variables in this case.

[ncoden]

There is no context to preserve. _this and other variables are not passed through the context.
We need setTimeout here to keep when same behavior (asynchronous call) when the document is ready or not.

[DanielRuf]

Take a look at the failing unit test(s) due to this ;-)

[ncoden]

Right, but this has nothing to do with the context, as this is not used.

https://github.com/ncoden/foundation-sites/blob/f353fc2f1a6d556a511734fa7eeacd0221cd064d/js/foundation.offcanvas.js#L169-L173

[ncoden]

The error comes from the component being already destroyed when the function in setTimeout is executed. I don't exactly know why, but the best solution would be to handle this case as we do for others events listeners: to unregister it on destroy.

[ncoden]

@DanielRuf I fixed the bug in tests caused by the onLoad event that was not cleared when the component was destroyed (so the event was called after the component is destroyed, with an empty this). Now I use an event in both cases, load or the custom _didLoad returned by onLoad so we can use:

const listener = onLoad($elem, handler);
...
$elem.off(listener);

[ncoden]

Thanks for the review.