remove redundant get_mime_type() function

Main.gd

@@ -67,18 +67,13 @@ func _serve_file(_request: HTTPServer.Request, response: HTTPServer.Response, bi
 
 		var mime := mime_types.get(file_name)
 		response.header("content-type", mime.full_type)
-		
+
 		# variant
 		# warning-ignore:incompatible_ternary
 		var data = f.get_as_text() if mime.type == 'text' else f.get_buffer(f.get_len())
 
 		response.data(data)
-		
+
 	else:
 		response.header("content-type", "text/plain")
 		response.data("500 - Read Error")
-
-
-func get_mime_type(file_name: String) -> String:
-	var ext := file_name.get_extension().to_lower()
-	return mime_types[ext] if ext in mime_types else "application/octet-stream"