chore: add changelog for #9411

Author: mgadewoll

packages/eui/changelogs/upcoming/9411.md

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+- Updated `EuiSelectableList` and `EuiSelectableListItem` styles
+- Updated `EuiSelectableListItem` to use `EuiCheckboxControl` for `singleSelection=false`
+- Updated `EuiSelectableList` to use `VariableSizeList` instead of `FixedSizeList` from `react-window`
+- Updated `EuiSelectableList` overflow scroll styles to use `animation-timeline`
+- Updated `EuiSelectableSearch`'s `compressed` default value to `true`
+
+**Breaking changes**
+
+- Removed `paddingSize` prop from `EuiSelectableList` and `EuiSelectableListItem`