Fix documentation in EV current formula generator

The EV current formula generator won't raise
`ComponentNotFound` because it is not looking for
a grid component while generating the formula.

Signed-off-by: Daniel Zullo <[email protected]>

Author: daniel-zullo-frequenz

src/frequenz/sdk/timeseries/logical_meter/_formula_generators/_ev_charger_current_formula.py

@@ -22,9 +22,6 @@ async def generate(self) -> FormulaEngine3Phase:
 
         Returns:
             A formula engine that calculates total 3-phase ev charger current values.
-
-        Raises:
-            ComponentNotFound: when the component graph doesn't have a `GRID` component.
         """
         component_graph = microgrid.get().component_graph
         ev_chargers = [