added interactive login for azure cognitive search vector store (#11360)

**Description:** Previously if the access to Azure Cognitive Search was
not done via an API key, the default credential was called which doesn't
allow to use an interactive login. I simply added the option to use
"INTERACTIVE" as a key name, and this will launch a login window upon
initialization of the AzureSearch object.

libs/langchain/langchain/vectorstores/azuresearch.py

@@ -77,7 +77,7 @@ def _get_search_client(
 ) -> SearchClient:
     from azure.core.credentials import AzureKeyCredential
     from azure.core.exceptions import ResourceNotFoundError
-    from azure.identity import DefaultAzureCredential
+    from azure.identity import DefaultAzureCredential, InteractiveBrowserCredential
     from azure.search.documents import SearchClient
     from azure.search.documents.indexes import SearchIndexClient
     from azure.search.documents.indexes.models import (
@@ -93,6 +93,9 @@ def _get_search_client(
     default_fields = default_fields or []
     if key is None:
         credential = DefaultAzureCredential()
+    elif key.upper() == "INTERACTIVE":
+        credential = InteractiveBrowserCredential()
+        credential.get_token("https://search.azure.com/.default")
     else:
         credential = AzureKeyCredential(key)
     index_client: SearchIndexClient = SearchIndexClient(