refactor: update test mocks to use addOutputOptions for consistency

- Replaced `outputOptions` with `addOutputOptions` in media service spec test to align with updated FFmpeg strategy.

backend/src/media/media.service.spec.ts

@@ -75,7 +75,7 @@ describe("MediaService", () => {
 				toFormat: jest.fn().mockReturnThis(),
 				videoCodec: jest.fn().mockReturnThis(),
 				audioCodec: jest.fn().mockReturnThis(),
-				outputOptions: jest.fn().mockReturnThis(),
+				addOutputOptions: jest.fn().mockReturnThis(),
 				on: jest.fn().mockImplementation(function (event, cb) {
 					if (event === "end") setTimeout(cb, 0);
 					return this;