feat: add GoogleGenAIMultimodalDocumentEmbedder to support gemini-embedding-2 (#2944)

* feat: add GoogleGenAIMultimodalDocumentEmbedder to support gemini-embedding-2

* refinements

* fix tests

Author: anakin87

integrations/google_genai/pydoc/config_docusaurus.yml

@@ -3,6 +3,7 @@ loaders:
       - haystack_integrations.components.generators.google_genai.chat.chat_generator
       - haystack_integrations.components.embedders.google_genai.document_embedder
       - haystack_integrations.components.embedders.google_genai.text_embedder
+      - haystack_integrations.components.embedders.google_genai.multimodal_document_embedder
     search_path: [../src]
 processors:
   - type: filter

integrations/google_genai/src/haystack_integrations/components/embedders/google_genai/__init__.py

@@ -2,6 +2,7 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 from .document_embedder import GoogleGenAIDocumentEmbedder
+from .multimodal_document_embedder import GoogleGenAIMultimodalDocumentEmbedder
 from .text_embedder import GoogleGenAITextEmbedder
 
-__all__ = ["GoogleGenAIDocumentEmbedder", "GoogleGenAITextEmbedder"]
+__all__ = ["GoogleGenAIDocumentEmbedder", "GoogleGenAIMultimodalDocumentEmbedder", "GoogleGenAITextEmbedder"]

integrations/google_genai/src/haystack_integrations/components/embedders/google_genai/document_embedder.py

@@ -101,7 +101,7 @@ def __init__(
             Required when using Vertex AI with Application Default Credentials.
         :param model:
             The name of the model to use for calculating embeddings.
-            The default model is `text-embedding-ada-002`.
+            The default model is `gemini-embedding-001`.
         :param prefix:
             A string to add at the beginning of each text.
         :param suffix: