[Bug] Tooltip formatter callback not firing for connected chart

### Version

6.0.0

### Link to Minimal Reproduction

https://codepen.io/misanek/pen/XJXRBQq

### Steps to Reproduce

1. create 2 charts with tooltips and async tooltip formatter ( `setTimeout` used in example)
2. add same group to those charts `myChart.group = "group1";`
3. connect charts using `echarts.connect("group1");`
4. hover over first chart, tooltip with value is shown
5. connected chart tooltip is stuck with `Loading` value ❌

### Current Behavior

1. Hover over one chart
2. Tooltip is shown and value changes from `Loading` to `Value: ${value}`
3. Connected chart tooltip is shown but it is stuck in `Loading` ❌

### Expected Behavior

1. Hover over one chart
2. Tooltip is shown and value changes from `Loading` to `Value: ${value}`
3. Connected chart tooltip is shown and value changes from `Loading` to `Value: ${value}`✅

### Environment

```markdown
- OS: Win 11
- Browser: Edge Version 141.0.3537.57 (Official build) (64-bit)
- Framework: none
```

### Any additional comments?

_No response_

Start with the linked CodePen minimal reproduction and trace how connected charts update tooltip content when the formatter uses setTimeout. Compare the tooltip update path for the hovered chart with the connected chart; done means both tooltips change from Loading to Value: ${value}.

Written by the indexing model from the issue text.