fix: Add input validation and retry mechanism to HuggingFaceEmbedding

[iamarunbrahma]

Description

This PR adds robust input validation and retry mechanism to the HuggingFaceEmbedding class to improve reliability and error handling. The changes include:

1. Validates if the text is empty or whitespace-only

2. Uses tenacity for automatic retries

These changes make the embedding process more robust by handling edge cases and transient failures gracefully.

New Package?

Did I fill in the tool.llamahub section in the pyproject.toml and provide a detailed README.md for my new integration or package?

• Yes
• No (modifying existing package)

Version Bump?

Did I bump the version in the pyproject.toml file of the package I am updating? (Except for the llama-index-core package)

• Yes (from 0.4.0 to 0.4.1)
• No

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• I added new unit tests to cover this change
  • Added test_input_validation for empty/whitespace input
  • Added test_embedding_retry for retry mechanism
  • Tests run successfully on Python 3.9, 3.10, 3.11, and 3.12

Suggested Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added Google Colab support for the newly added notebooks
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I ran make format; make lint to appease the lint gods