Show 'reconnecting' message when sync loop is disconnected

With this change I'm also taking care to not show the standard "Connection to the server has been lost" banner in the call view, since that is now covered by the 'reconnecting' message.

src/Header.tsx

@@ -17,27 +17,38 @@ import Logo from "./icons/Logo.svg?react";
 import { Avatar, Size } from "./Avatar";
 import { EncryptionLock } from "./room/EncryptionLock";
 import { useMediaQuery } from "./useMediaQuery";
+import { DisconnectedBanner } from "./DisconnectedBanner";
 
 interface HeaderProps extends HTMLAttributes<HTMLElement> {
   ref?: Ref<HTMLElement>;
   children: ReactNode;
   className?: string;
+  /**
+   * Whether the header should display an informational banner whenever the
+   * client is disconnected from the homeserver.
+   * @default true
+   */
+  disconnectedBanner?: boolean;
 }
 
 export const Header: FC<HeaderProps> = ({
   ref,
   children,
   className,
+  disconnectedBanner = true,
   ...rest
 }) => {
   return (
-    <header
-      ref={ref}
-      className={classNames(styles.header, className)}
-      {...rest}
-    >
-      {children}
-    </header>
+    <>
+      <header
+        ref={ref}
+        className={classNames(styles.header, className)}
+        {...rest}
+      >
+        {children}
+      </header>
+      {disconnectedBanner && <DisconnectedBanner />}
+    </>
   );
 };