feat(genai): support optional `seed` parameter#1356

Odessit007 wants to merge 2 commits intolangchain-ai:mainlangchain-ai/langchain-google:mainfrom

Odessit007:feature/seed_parameter_for_google_genaiOdessit007/langchain-google:feature/seed_parameter_for_google_genaiCopy head branch name to clipboard