[IconButton] Improve onClick warning

Not sure where to put this, but I’m getting the warning:

Failed prop type: Material-UI: You are providing an onClick event listener to a child of a button element.
Firefox will never trigger the event.
You should move the onClick listener to the parent button element.

• The issue is present in the latest release.
• I have searched the issues of this repository and believe that this is not a duplicate.

Current Behavior 😯

Warning thrown

Expected Behavior 🤔

Warning is a non-issue (in Firefox, from what I gather, in this situation), so this warning shouldn’t be there.

I get why this is being thrown, the expand icon is wrapped in a button base (IconButton), but I feel like the warning is misleading.

Also, curious to know if you guys had a conversation about ever giving users the ability to pass a function to the IconButton component? If not, I wouldn’t mind making a PR. Not sure how it would look like yet, but what would be wrong with something like,

type TAccordion = {
       . . . . .
       onExpandIconClick: (...params: any[]) => any;
}

const AccordionSummary = React.forwardRef(function AccordionSummary(props, ref) {
   const {
        onExpandIconClick,
        classes,
        expandIcon,
        IconButtonProps = {},
        ...other
   } = props;
   . . . . .
   return {
   . . . . .
    {expandIcon && (
        <IconButton
            onClick={onExpandIconClick}
            edge='end'
            component='div'
            tabIndex={null}
            role={null}
            aria-hidden
            {...IconButtonProps}
            className={clsx(
                classes.expandIcon,
                {
                    [classes.expanded]: expanded,
                },
                IconButtonProps.className,
            )}
        >
            {expandIcon}
        </IconButton>
    )}

Steps to Reproduce 🕹

[croraf]

I will make this PR tomorrow (if I dont forget) so the others can also comment if it makes sense. @mkhoussid the conclusion for you is as per said before. You shouldn’t use expandIcon for this, but do it by appropriately laying out the children of AccordionSummary.

[croraf]

@pranjanpr yes.

Also there is an unrelated second issue that I’m doing a PR for (you can see the PR link slightly above), which is slightly more advanced.