[Test] Unit Tests for ReleaseNotificationWorker

[mukesh-5059]

Difficulty: Hard
Location: app/src/test/java/com/example/movies_db/worker/ReleaseNotificationWorkerTest.kt
Description:

• Use TestListenableWorkerBuilder.
• Mock MovieDao to return specific movies with today's date.
• Assert that the worker returns Success.
• Verify (via Spy/Mock) that the Notification Manager would have been called.