Fix call to detect ODM reconstruction file (nerfstudio-project#3018)

Author: codeprimate

nerfstudio/process_data/odm_utils.py

@@ -136,7 +136,7 @@ def cameras2nerfds(
     shots_dict = {}
     reconstruction = None
 
-    if reconstruction_file.exists:
+    if reconstruction_file.exists():
         reconstruction = get_reconstruction(reconstruction_file)
         shots = reconstruction.get("shots", [])
         for filename in shots: