Remove exception for missing metadata (#170)

Co-authored-by: Baudouin Raoult <[email protected]>

Author: JPXKQX

Diff for: src/anemoi/datasets/data/join.py

@@ -131,8 +131,6 @@ def variables_metadata(self):
                 if v not in result:
                     LOG.error("Missing metadata for %r.", v)
 
-            raise ValueError("Some variables are missing metadata.")
-
         return result
 
     @cached_property