community[patch]: Load list of files using UnstructuredFileLoader (#16216)

- **Description:** Updated `_get_elements()` function of
`UnstructuredFileLoader `class to check if the argument self.file_path
is a file or list of files. If it is a list of files then it iterates
over the list of file paths, calls the partition function for each one,
and appends the results to the elements list. If self.file_path is not a
list, it calls the partition function as before.
  
  - **Issue:** Fixed #15607,
  - **Dependencies:** NA
  - **Twitter handle:** NA

Co-authored-by: H161961 <Raunak.Raunak@Honeywell.com>

libs/community/langchain_community/document_loaders/unstructured.py

@@ -170,7 +170,13 @@ class UnstructuredFileLoader(UnstructuredBaseLoader):
     def _get_elements(self) -> List:
         from unstructured.partition.auto import partition
 
-        return partition(filename=self.file_path, **self.unstructured_kwargs)
+        if isinstance(self.file_path, list):
+            elements = []
+            for file in self.file_path:
+                elements.extend(partition(filename=file, **self.unstructured_kwargs))
+            return elements
+        else:
+            return partition(filename=self.file_path, **self.unstructured_kwargs)
 
     def _get_metadata(self) -> dict:
         return {"source": self.file_path}