embeddings: nomic embed vision (#22482)

Thank you for contributing to LangChain!

**Description:** Adds Langchain support for Nomic Embed Vision
**Twitter handle:** nomic_ai,zach_nussbaum


- [x] **Add tests and docs**: If you're adding a new integration, please
include
1. a test for the integration, preferably unit tests that do not rely on
network access,
2. an example notebook showing its use. It lives in
`docs/docs/integrations` directory.


- [ ] **Lint and test**: Run `make format`, `make lint` and `make test`
from the root of the package(s) you've modified. See contribution
guidelines for more: https://python.langchain.com/docs/contributing/

Additional guidelines:
- Make sure optional dependencies are imported within a function.
- Please do not add dependencies to pyproject.toml files (even optional
ones) unless they are required for unit tests.
- Most PRs should not touch more than one package.
- Changes should be backwards compatible.
- If you are adding something to community, do not re-import it in
langchain.

If no one reviews your PR within a few days, please @-mention one of
baskaryan, efriis, eyurtsev, ccurme, vbarda, hwchase17.

---------

Co-authored-by: Lance Martin <122662504+rlancemartin@users.noreply.github.com>
Co-authored-by: Bagatur <baskaryan@gmail.com>

libs/partners/nomic/langchain_nomic/embeddings.py

@@ -22,6 +22,7 @@ class NomicEmbeddings(Embeddings):
         self,
         *,
         model: str,
+        nomic_api_key: Optional[str] = ...,
         dimensionality: Optional[int] = ...,
         inference_mode: Literal["remote"] = ...,
     ):
@@ -32,6 +33,7 @@ class NomicEmbeddings(Embeddings):
         self,
         *,
         model: str,
+        nomic_api_key: Optional[str] = ...,
         dimensionality: Optional[int] = ...,
         inference_mode: Literal["local", "dynamic"],
         device: Optional[str] = ...,
@@ -43,6 +45,7 @@ class NomicEmbeddings(Embeddings):
         self,
         *,
         model: str,
+        nomic_api_key: Optional[str] = ...,
         dimensionality: Optional[int] = ...,
         inference_mode: str,
         device: Optional[str] = ...,
@@ -57,6 +60,7 @@ class NomicEmbeddings(Embeddings):
         dimensionality: Optional[int] = None,
         inference_mode: str = "remote",
         device: Optional[str] = None,
+        vision_model: Optional[str] = None,
     ):
         """Initialize NomicEmbeddings model.
 
@@ -80,6 +84,7 @@ class NomicEmbeddings(Embeddings):
         self.dimensionality = dimensionality
         self.inference_mode = inference_mode
         self.device = device
+        self.vision_model = vision_model
 
     def embed(self, texts: List[str], *, task_type: str) -> List[List[float]]:
         """Embed texts.
@@ -121,3 +126,9 @@ class NomicEmbeddings(Embeddings):
             texts=[text],
             task_type="search_query",
         )[0]
+
+    def embed_image(self, uris: List[str]) -> List[List[float]]:
+        return embed.image(
+            images=uris,
+            model=self.vision_model,
+        )["embeddings"]