Various fixes (#11448)

# Scrollbar fix

Fixes https://github.com/twentyhq/twenty/issues/11403

<img width="1512" alt="image"
src="https://github.com/user-attachments/assets/b13fe0f2-8c61-4ea8-9ea1-e61e571a90da"
/>

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Co-authored-by: Félix Malfait <felix.malfait@gmail.com>

packages/twenty-front/src/modules/ui/layout/modal/components/Modal.tsx

@@ -257,3 +257,4 @@ export const Modal = ({
 Modal.Header = ModalHeader;
 Modal.Content = ModalContent;
 Modal.Footer = ModalFooter;
+Modal.Backdrop = StyledBackDrop;