fix(date-picker-compat): onIconClick triggering useOnClickOutside (microsoft#35114)

Author: ValentinaKozlova

change/@fluentui-react-datepicker-compat-28d17cbb-bb56-4bf2-965e-c60ae8d98a2c.json

@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "fix: onIconClick triggering useOnClickOutside",
+  "packageName": "@fluentui/react-datepicker-compat",
+  "email": "vkozlova@microsoft.com",
+  "dependentChangeType": "patch"
+}

packages/react-components/react-datepicker-compat/library/src/components/DatePicker/useDatePicker.tsx

@@ -346,6 +346,7 @@ export const useDatePicker_unstable = (props: DatePickerProps, ref: React.Ref<HT
   ]);
 
   const onIconClick = (ev: React.MouseEvent<HTMLElement>): void => {
+    ev.preventDefault();
     ev.stopPropagation();
     if (!open && !props.disabled) {
       showDatePickerPopup();