Changes

PR #2004 by ksylvan: Add i18n translations for VertexAI, Gemini, Bedrock, and fetch plugins

• Add i18n translations for VertexAI, Gemini, Bedrock, and fetch plugins across 10 locale files
• Replace hardcoded English strings with i18n.T() calls in Bedrock, Gemini, VertexAI, and fetch plugins
• Add error handling for fetch operations with new error messages in i18n
• Use errors.New instead of fmt.Errorf for non-formatted error strings
• Add Gemini TTS and audio error translations, AWS Bedrock client error translations, and fetch plugin error translations to all locales