Set webdav plugin to use temp files by default

it avoids the issue with loading the entire files into memory.

lib/galaxy/files/sources/webdav.py

@@ -3,6 +3,7 @@ try:
 except ImportError:
     WebDAVFS = None
 
+import tempfile
 from typing import (
     Optional,
     Union,
@@ -22,6 +23,11 @@ class WebDavFilesSource(PyFilesystem2FilesSource):
 
     def _open_fs(self, user_context=None, opts: Optional[FilesSourceOptions] = None):
         props = self._serialization_props(user_context)
+        use_temp_files = props.pop("use_temp_files", None)
+        if use_temp_files is None:
+            # Default to True to avoid memory issues with large files.
+            props["use_temp_files"] = True
+            props["temp_path"] = props.get("temp_path", tempfile.gettempdir())
         extra_props: Union[FilesSourceProperties, dict] = opts.extra_props or {} if opts else {}
         handle = WebDAVFS(**{**props, **extra_props})
         return handle