Fixes #3665
Closes #4473

A filter works by binding a watch callback and its args every time the watcher fires. This bound function is then held back until your "filter" calls its invoke parameter.

In debounceFilter, we setup a maxWait timer to fire after a certain amount of time. Once this fires, it calls invoke.

The problem here is that the invoke will be the paired cb/args from the point in time where we started the timer.

For example:

const cb = vi.fn();
const someRef = ref(0);

watchWithFilter(
  someRef,
  cb,
  {
    eventFilter: debounceFilter(100, {maxWait: 500})
  }
);

someRef.value = 1; // cb(1, 0) is held back, `maxWait` timer is kicked off _with `invoke = () => cb(1, 0)`_
someRef.value = 2; // cb(2, 0)
// somehow 500ms passes
// maxWait timer now calls `cb(1, 0)` rather than cb(2, 0)

To fix this, i've added lastInvoker, which is the last invoke function we created for this filter. Once the max timer fires, we will clear the regular timer, and call lastInvoker (which a regular timer originally set up).

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