fix: files settings save issue

Author: tjbck

backend/open_webui/routers/retrieval.py

@@ -1042,13 +1042,25 @@ async def update_rag_config(
     )
 
     # File upload settings
-    request.app.state.config.FILE_MAX_SIZE = form_data.FILE_MAX_SIZE
-    request.app.state.config.FILE_MAX_COUNT = form_data.FILE_MAX_COUNT
+    request.app.state.config.FILE_MAX_SIZE = (
+        form_data.FILE_MAX_SIZE
+        if form_data.FILE_MAX_SIZE is not None
+        else request.app.state.config.FILE_MAX_SIZE
+    )
+    request.app.state.config.FILE_MAX_COUNT = (
+        form_data.FILE_MAX_COUNT
+        if form_data.FILE_MAX_COUNT is not None
+        else request.app.state.config.FILE_MAX_COUNT
+    )
     request.app.state.config.FILE_IMAGE_COMPRESSION_WIDTH = (
         form_data.FILE_IMAGE_COMPRESSION_WIDTH
+        if form_data.FILE_IMAGE_COMPRESSION_WIDTH is not None
+        else request.app.state.config.FILE_IMAGE_COMPRESSION_WIDTH
     )
     request.app.state.config.FILE_IMAGE_COMPRESSION_HEIGHT = (
         form_data.FILE_IMAGE_COMPRESSION_HEIGHT
+        if form_data.FILE_IMAGE_COMPRESSION_HEIGHT is not None
+        else request.app.state.config.FILE_IMAGE_COMPRESSION_HEIGHT
     )
     request.app.state.config.ALLOWED_FILE_EXTENSIONS = (
         form_data.ALLOWED_FILE_EXTENSIONS