Calling window close callback after popping the value from store

[VatsalP]

Description

In the current case, if a window is to be closed the start timestamp of the current window is checked against last_closed_window.

if keys_to_remove:
    for key in keys_to_remove:
        value = self.data.pop(key, None)
        if key[1][0] > self.last_closed_window:
            await self.on_window_close(key, value)
    self.last_closed_window = max(
        self.last_closed_window,
        max(key[1][0] for key in keys_to_remove),
    )

Which means in this case if we are using relative_to_field for a Windowed Table and event comes with some old timestamp which is lesser than last_closed_window, then the value would already be popped but the on_window_close wouldn't be called.

Ideally if window is closed we should be calling the on_window_close callback