Adding anonymizeSnippets in reports config

[dristysrivastava]

Changes:

• Added anonymizedSnippets in `reports' section in config
  • If anonymizedSnippets will be there in both reprt and classifier. It will give following error:

- If `anonymizedSnippets` will be there in `classifier`, following deprecation message will be shown:

• Updated config custom validation with pydanticV2 model validation

• When pebblo server exists due to validation failure, now it will exits with failure message:

  • Before (Earlier it was failing with following messages)

- After (Now)

• Updated /loader/doc API (for both file and DB) with latest config chaneg for anonymizeSnippets.
• Updated Unit test cases for config validation