add enterpriseWebSearch tool support

[elentaure]

Description:

• Add support for web grounding for enterprise according to https://docs.cloud.google.com/vertex-ai/generative-ai/docs/grounding/web-grounding-enterprise

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)

[narengogi]

@elentaure please run npm run format and dont skip the git hooks 😵‍💫