refactor(sidebar): remove isShared prop from ChatListItem and Sidebar components

- Removed the isShared prop from ChatListItemProps interface and its usage in the Sidebar component to simplify the code and improve clarity.

surfsense_web/components/layout/ui/sidebar/ChatListItem.tsx

@@ -19,7 +19,6 @@ import { sidebarListItemClassName } from "./SidebarListItem";
 interface ChatListItemProps {
 	name: string;
 	isActive?: boolean;
-	isShared?: boolean;
 	archived?: boolean;
 	dropdownOpen?: boolean;
 	onDropdownOpenChange?: (open: boolean) => void;

surfsense_web/components/layout/ui/sidebar/Sidebar.tsx

@@ -316,7 +316,6 @@ export function Sidebar({
 												key={chat.id}
 												name={chat.name}
 												isActive={chat.id === activeChatId}
-												isShared={chat.visibility === "SEARCH_SPACE"}
 												archived={chat.archived}
 												dropdownOpen={openDropdownChatId === chat.id}
 												onDropdownOpenChange={(open) =>