Simplifying Particle.__getattr__

@VeckoTheGecko, you were right that this if-statement wasn't needed

Author: erikvansebille

parcels/particle.py

@@ -115,8 +115,6 @@ def __init__(self, data: xr.Dataset, index: int):
         self._index = index
 
     def __getattr__(self, name):
-        if name in ["_data", "_index"]:
-            return object.__getattribute__(self, name)
         _data = object.__getattribute__(self, "_data")
         return _data[name].values[self._index]