fix(lint): drop unused import, suppress PLR0915 on batch_embeddings

- F401: _is_multimodal_input was orphaned by an earlier helper extraction
  (b038c0714c) — remove the dead import.
- PLR0915: batch_embeddings is 51 statements (limit 50), one over the
  threshold. Suppress with # noqa, matching the existing convention used
  in utils.py, cost_calculator.py, and get_llm_provider_logic.py.

litellm/llms/vertex_ai/gemini_embeddings/batch_embed_content_handler.py

@@ -23,7 +23,6 @@ from litellm.types.utils import EmbeddingResponse
 from ..gemini.vertex_and_google_ai_studio_gemini import VertexLLM
 from .batch_embed_content_transformation import (
     _is_file_reference,
-    _is_multimodal_input,
     process_embed_content_response,
     process_response,
     transform_openai_input_gemini_content,
@@ -125,7 +124,7 @@ class GoogleBatchEmbeddings(VertexLLM):
 
         return resolved_files
 
-    def batch_embeddings(
+    def batch_embeddings(  # noqa: PLR0915
         self,
         model: str,
         input: EmbeddingInput,