docs: enhance data format examples in customization guide

[Pavan-Microsoft]

Purpose

This pull request updates the data customization documentation to provide clearer guidance and additional examples for required data formats. The main improvement is making it easier for users to understand how to format their own data and where to find sample files.

Documentation improvements:

• Clarified the required naming convention for data files and added a reference to sample transcripts and audio data in /infra/data/telecom for users to review. Also provided explicit examples for both transcript (.json) and audio (.wav) files.

Does this introduce a breaking change?

• Yes
• No

Golden Path Validation

• I have tested the primary workflows (the "golden path") to ensure they function correctly without errors.

Deployment Validation

• I have validated the deployment process successfully and all services are running as expected with this change.