feat: improve video conference UI in EventModal

- Replace 'Meeting link generated' text with 'Join Visio conference' button
- Button opens video conference link in new tab when clicked
- Use contained variant styling to match Save button appearance
- Maintain copy and delete functionality for meeting links

src/features/User/LoginCallback.tsx

@@ -1,6 +1,6 @@
 import { useEffect, useRef } from "react";
 import { Callback } from "./oidcAuth";
-import { useAppDispatch, useAppSelector } from "../../app/hooks";
+import { useAppDispatch } from "../../app/hooks";
 import { push } from "redux-first-history";
 import { getOpenPaasUserDataAsync, setTokens, setUserData } from "./userSlice";
 import { Loading } from "../../components/Loading/Loading";