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/setupTests.ts

@@ -1,7 +1,6 @@
 import "@testing-library/jest-dom";
 
-import { TextEncoder, TextDecoder } from "util";
-import { clientConfig } from "./features/User/oidcAuth";
+import { TextEncoder } from "util";
 
 global.TextEncoder = TextEncoder;