fix: markdown proc will remove image (#5855)

api/core/rag/extractor/markdown_extractor.py

     def __init__(
             self,
             file_path: str,
-            remove_hyperlinks: bool = True,
-            remove_images: bool = True,
+            remove_hyperlinks: bool = False,
+            remove_images: bool = False,
             encoding: Optional[str] = None,
             autodetect_encoding: bool = True,
     ):