Start using the new modal component

This attempts to converge all our modals on the new modal component while changing their designs as little as possible. This should reduce the bundle size a bit and make the app generally feel like it's converging on the new designs, even though individual modals still remain to be revamped.

src/home/JoinExistingCallModal.tsx

@@ -17,36 +17,29 @@ limitations under the License.
 import { PressEvent } from "@react-types/shared";
 import { useTranslation } from "react-i18next";
 
-import { Modal, ModalContent } from "../Modal";
+import { Modal } from "../Modal";
 import { Button } from "../button";
 import { FieldRow } from "../input/Input";
 import styles from "./JoinExistingCallModal.module.css";
 
 interface Props {
+  open: boolean;
+  onDismiss: () => void;
   onJoin: (e: PressEvent) => void;
-  onClose: () => void;
-  // TODO: add used parameters for <Modal>
-  [index: string]: unknown;
 }
-export function JoinExistingCallModal({ onJoin, onClose, ...rest }: Props) {
+
+export function JoinExistingCallModal({ onJoin, open, onDismiss }: Props) {
   const { t } = useTranslation();
 
   return (
-    <Modal
-      title={t("Join existing call?")}
-      isDismissable
-      {...rest}
-      onClose={onClose}
-    >
-      <ModalContent>
-        <p>{t("This call already exists, would you like to join?")}</p>
-        <FieldRow rightAlign className={styles.buttons}>
-          <Button onPress={onClose}>{t("No")}</Button>
-          <Button onPress={onJoin} data-testid="home_joinExistingRoom">
-            {t("Yes, join call")}
-          </Button>
-        </FieldRow>
-      </ModalContent>
+    <Modal title={t("Join existing call?")} open={open} onDismiss={onDismiss}>
+      <p>{t("This call already exists, would you like to join?")}</p>
+      <FieldRow rightAlign className={styles.buttons}>
+        <Button onPress={onDismiss}>{t("No")}</Button>
+        <Button onPress={onJoin} data-testid="home_joinExistingRoom">
+          {t("Yes, join call")}
+        </Button>
+      </FieldRow>
     </Modal>
   );
 }