Fix UpdateButton with custom notification doesn't close the confirmation dialog

[fzaninotto]

Closes #9194

[slax57]

FTR I don't agree with this fix.
To me this is just moving the issue to another place.

The root issue is not being able to close the dialog from within a side-effect fn, like onSuccess. We should instead provide a callback for that as an extra argument, that can be called in user land.

With this fix, the problem is no longer there if we provide a custom onSuccess, but we will have the same issue if we override the onSettled.
Besides, this is also technically a BC as, from now on, the dialog will also close in case of an error, while it would have remained open in the previous version (which makes it easier to retry the update).

[fzaninotto]

You're absolutely right about the BC, I didn't see it. I'll reopen the issue.

[slax57]

You're absolutely right about the BC, I didn't see it. I'll reopen the issue.

My bad! Reviewing PR #9208 made me realize that setOpen(false) used to be both in onSuccess and onError, so there is no BC!

However the rest of my comment is still valid I believe. Wdyt? Shoud we keep the fix or work on a better one?