Adding tavily as a plugin integration

[manisrinivasan2k1]

• Added Tavily as a guardrail plugin for online search enrichment

Description: (required)

• Added a new tavily.online guardrail that calls Tavily Search before inference and injects fresh web search context into chat and completion prompts
• Added support for Tavily search parameters and response metadata, including answer/raw content/images/favicon handling, plus tests covering prompt injection and request mapping

Tests Run/Test cases added: (required)

• Added tests for chat and completion prompt enrichment, custom prefix/suffix handling, request parameter mapping, image handling for both string and object formats, and parameter gating for safeSearch, country, chunksPerSource, and autoParameters

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)
• Documentation update
• Refactoring (no functional changes)