docs(MessageView): adjust dialog example (#5993)

Closes #5990

Author: Lukas742

packages/main/src/components/MessageView/MessageView.mdx

@@ -53,6 +53,7 @@ function MyComponent() {
   const [isOnDetailsPage, setIsOnDetailsPage] = useState(false);
   return (
     <Dialog
+      style={{ width: '500px' }}
       className="modal-without-padding"
       header={
         <Bar

packages/main/src/components/MessageView/MessageView.stories.tsx

@@ -123,7 +123,7 @@ export const MessageViewInDialog: Story = {
           Open Dialog
         </Button>
         <Dialog
-          style={{ width: '400px' }}
+          style={{ width: '500px' }}
           className="contentPartNoPadding headerPartNoPadding"
           open={open}
           onClose={() => {