Enhancements: Better input prompts, handling empty lists, and user feedbackEnhance video manager: improved input handling and empty list checks

[karmakr1920]

Changes Made:

1. Update Video:

• Shows a friendly message when there are no videos available to update.
• Handles invalid or empty input gracefully.

2. Delete Video:

• Shows a clear message when no videos exist to delete.
• After deletion, a confirmation message is displayed.

3. User Prompts:

• Improved clarity in input prompts to guide users better.

4. Error Handling:

• Prevents crashes when the user provides non-integer or out-of-range input.
• Ensures functions exit early if the video list is empty.