multiple: Remove unnecessary Ruff suppression comments (#21050)

## Summary

I ran `ruff check --extend-select RUF100 -n` to identify `# noqa`
comments that weren't having any effect in Ruff, and then `ruff check
--extend-select RUF100 -n --fix` on select files to remove all of the
unnecessary `# noqa: F401` violations. It's possible that these were
needed at some point in the past, but they're not necessary in Ruff
v0.1.15 (used by LangChain) or in the latest release.

Co-authored-by: Erick Friis <erick@langchain.dev>

libs/partners/openai/langchain_openai/embeddings/base.py

@@ -275,7 +275,7 @@ class OpenAIEmbeddings(BaseModel, Embeddings):
         # If tiktoken flag set to False
         if not self.tiktoken_enabled:
             try:
-                from transformers import AutoTokenizer  # noqa: F401
+                from transformers import AutoTokenizer
             except ImportError:
                 raise ValueError(
                     "Could not import transformers python package. "