MultiSelect (group) SelectAll checked when all items in first group are selected

[pingxiong620]

Describe the bug

Create a React MultiSelect with group options, when all the children under the first group are selected, the SelectAll checkbox on the header gets selected as well even though items under other groups are unselected. This issue can be easily reproduced on the Demo page
https://primereact.org/multiselect/
or
https://www.primefaces.org/primereact-v8/multiselect/

Reproducer

No response

PrimeReact version

8.x and 9.x, all versions

React version

17.x

Language

TypeScript

Build / Runtime

Create React App (CRA)

Browser(s)

No response

Steps to reproduce the behavior

1. Navigate to React MultiSelect component demo page, either 8.x or 9.x
   https://www.primefaces.org/primereact-v8/multiselect/
   or
   https://primereact.org/multiselect/
2. Locate the Grouped MultiSelect
3. Click to open the Grouped Multiselect
4. Select all 4 cities under Germany
5. Observe that the SelectAll checkbox is selected.

Expected behavior

Since only children under the first city get selected, children under other cities have not been selected, the SelectAll checkbox should not be selected.