community[minor]: S3FileLoader to use expose mode and post_processors arguments of unstructured loader (#19270)

**Description:** Update s3_file.py to use arguments **mode** and
**post_processors** from the base class **UnstructuredBaseLoader** to
include more metadata about the files from the S3 bucket such as
*'page_number', 'languages'* etc.

**Issue:** NA
**Dependencies:** None
**Twitter handle:** preak95

---------

Co-authored-by: ccurme <chester.curme@gmail.com>
Co-authored-by: Bagatur <22008038+baskaryan@users.noreply.github.com>

libs/community/langchain_community/document_loaders/s3_file.py

@@ -2,7 +2,7 @@ from __future__ import annotations
 
 import os
 import tempfile
-from typing import TYPE_CHECKING, List, Optional, Union
+from typing import TYPE_CHECKING, Callable, List, Optional, Union
 
 from langchain_community.document_loaders.unstructured import UnstructuredBaseLoader
 
@@ -27,6 +27,8 @@ class S3FileLoader(UnstructuredBaseLoader):
         aws_secret_access_key: Optional[str] = None,
         aws_session_token: Optional[str] = None,
         boto_config: Optional[botocore.client.Config] = None,
+        mode: str = "single",
+        post_processors: Optional[List[Callable]] = None,
     ):
         """Initialize with bucket and key name.
 
@@ -82,8 +84,12 @@ class S3FileLoader(UnstructuredBaseLoader):
             object is set on the session, the config object used when creating
             the client will be the result of calling ``merge()`` on the
             default config with the config provided to this call.
+        :param mode: Mode in which to read the file. Valid options are: single,
+        paged and elements
+        :param post_processors: Post processing functions to be applied to
+        extracted elements
         """
-        super().__init__()
+        super().__init__(mode, post_processors)
         self.bucket = bucket
         self.key = key
         self.region_name = region_name