Explanation

This PR addresses the issue where the Oppia Android app crashes when switching to landscape orientation after interacting with previous responses in the Exploration/Question player. The crash occurs due to uninitialized state when loading audio content. This fix ensures that the state is properly initialized before attempting to load the audio, preventing the app from crashing.

Changes Made:

• Added a check to ensure the state is initialized before loading audio content, preventing the app from crashing during orientation changes after interacting with previous responses.
• Added a test to verify that the app no longer crashes when switching to landscape orientation after interacting with previous responses.

Fixes #5657: App crashes when changing configuration to landscape after interacting with previous responses.

Essential Checklist

• The PR title and explanation each start with "Fix #bugnum: ".
• Any changes to scripts/assets files have their rationale included in the PR explanation.
• The PR follows the style guide.
• The PR does not contain any unnecessary code changes from Android Studio (reference).
• The PR is made from a branch that's not called "develop" and is up-to-date with "develop".
• The PR is assigned to the appropriate reviewers (reference).

Before :-
https://github.com/user-attachments/assets/0ee8de2f-45f2-4b2a-af57-0a371b6f34b2

After :-
https://github.com/user-attachments/assets/3b3a3be8-b80c-43b2-ba68-ffa3aa03ed3d