Fix 'icon' prop typing for ConfirmButton component

[andrii-i]

Fixes 'icon' prop typing for ConfirmButton component.

As mentioned in #383 (comment), ConfirmDialogButton component always uses icon prop as an instantiated element. Passing a class instead (possibility suggested by the use of OverridableComponent & {muiName: string;} type) would cause an error.

jupyter-scheduler/src/components/confirm-buttons.tsx

Lines 52 to 54 in f58284e

	<IconButton title={props.name} onClick={_ => setClicked(true)}>
	{props.icon}
	</IconButton>

Without this PR:

With this PR:

[github-actions]

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