qdrant[patch]: Use collection_exists API instead of exceptions (#22764)

## Description

Currently, the Qdrant integration relies on exceptions raised by
[`get_collection`
](https://qdrant.tech/documentation/concepts/collections/#collection-info)
to check if a collection exists.

Using
[`collection_exists`](https://qdrant.tech/documentation/concepts/collections/#check-collection-existence)
is recommended to avoid missing any unhandled exceptions. This PR
addresses this.

## Testing
All integration and unit tests pass. No user-facing changes.

libs/partners/qdrant/langchain_qdrant/vectorstores.py

@@ -23,14 +23,12 @@ from typing import (
 )
 
 import numpy as np
-from grpc import RpcError  # type: ignore
 from langchain_core.documents import Document
 from langchain_core.embeddings import Embeddings
 from langchain_core.runnables.config import run_in_executor
 from langchain_core.vectorstores import VectorStore
 from qdrant_client import AsyncQdrantClient, QdrantClient
 from qdrant_client.http import models
-from qdrant_client.http.exceptions import UnexpectedResponse
 from qdrant_client.local.async_qdrant_local import AsyncQdrantLocal
 
 from langchain_qdrant._utils import maximal_marginal_relevance
@@ -1636,14 +1634,16 @@ class Qdrant(VectorStore):
             path=path,
             **kwargs,
         )
-        try:
-            # Skip any validation in case of forced collection recreate.
-            if force_recreate:
-                raise ValueError
+        collection_exists = client.collection_exists(collection_name)
 
+        if collection_exists and force_recreate:
+            client.delete_collection(collection_name)
+            collection_exists = False
+
+        if collection_exists:
             # Get the vector configuration of the existing collection and vector, if it
             # was specified. If the old configuration does not match the current one,
-            # an exception is being thrown.
+            # an exception is raised.
             collection_info = client.get_collection(collection_name=collection_name)
             current_vector_config = collection_info.config.params.vectors
             if isinstance(current_vector_config, dict) and vector_name is not None:
@@ -1700,7 +1700,7 @@ class Qdrant(VectorStore):
                     f"If you want to recreate the collection, set `force_recreate` "
                     f"parameter to `True`."
                 )
-        except (UnexpectedResponse, RpcError, ValueError):
+        else:
             vectors_config = models.VectorParams(
                 size=vector_size,
                 distance=models.Distance[distance_func],
@@ -1714,8 +1714,6 @@ class Qdrant(VectorStore):
                     vector_name: vectors_config,
                 }
 
-            if client.collection_exists(collection_name):
-                client.delete_collection(collection_name)
             client.create_collection(
                 collection_name=collection_name,
                 vectors_config=vectors_config,
@@ -1795,14 +1793,17 @@ class Qdrant(VectorStore):
             path=path,
             **kwargs,
         )
-        try:
-            # Skip any validation in case of forced collection recreate.
-            if force_recreate:
-                raise ValueError
 
+        collection_exists = client.collection_exists(collection_name)
+
+        if collection_exists and force_recreate:
+            client.delete_collection(collection_name)
+            collection_exists = False
+
+        if collection_exists:
             # Get the vector configuration of the existing collection and vector, if it
             # was specified. If the old configuration does not match the current one,
-            # an exception is being thrown.
+            # an exception is raised.
             collection_info = client.get_collection(collection_name=collection_name)
             current_vector_config = collection_info.config.params.vectors
             if isinstance(current_vector_config, dict) and vector_name is not None:
@@ -1861,7 +1862,7 @@ class Qdrant(VectorStore):
                     f"recreate the collection, set `force_recreate` parameter to "
                     f"`True`."
                 )
-        except (UnexpectedResponse, RpcError, ValueError):
+        else:
             vectors_config = models.VectorParams(
                 size=vector_size,
                 distance=models.Distance[distance_func],
@@ -1875,7 +1876,7 @@ class Qdrant(VectorStore):
                     vector_name: vectors_config,
                 }
 
-            client.recreate_collection(
+            client.create_collection(
                 collection_name=collection_name,
                 vectors_config=vectors_config,
                 shard_number=shard_number,