fix(deps): bump google-genai minimum to >=1.64.0 for gemini-embedding-2-preview

The gemini-embedding-2-preview model requires the Vertex AI
:embedContent endpoint instead of the legacy :predict endpoint used
by older models (text-embedding-004, text-embedding-005).

In google-genai <1.64.0, embed_content() unconditionally routed to
:predict on Vertex AI, which returns FAILED_PRECONDITION for this
model.

v1.64.0 (googleapis/python-genai@af40cc6) introduced model-aware
dispatch in embed_content(): models with "gemini" in the name are
routed to :embedContent via t_is_vertex_embed_content_model(), while
older text-embedding-* models continue to use :predict.

This version also enforces a single-content-per-call limit for the
embedContent API, which is why FilesRetrieval sets embed_batch_size=1.

Co-authored-by: Xiang (Sean) Zhou <seanzhougoogle@google.com>
PiperOrigin-RevId: 883689438

Author: seanzhougoogle

pyproject.toml

@@ -44,7 +44,7 @@ dependencies = [
   "google-cloud-spanner>=3.56.0, <4.0.0",                    # For Spanner database
   "google-cloud-speech>=2.30.0, <3.0.0",                     # For Audio Transcription
   "google-cloud-storage>=2.18.0, <4.0.0",                    # For GCS Artifact service
-  "google-genai>=1.56.0, <2.0.0",                            # Google GenAI SDK
+  "google-genai>=1.64.0, <2.0.0",                            # Google GenAI SDK
   "graphviz>=0.20.2, <1.0.0",                                # Graphviz for graph rendering
   "httpx>=0.27.0, <1.0.0",                                   # HTTP client library
   "jsonschema>=4.23.0, <5.0.0",                              # Agent Builder config validation