refactor: remove VariableNoiseType

Author: AayushSabharwal

src/systems/model_parsing.jl

@@ -186,7 +186,6 @@ function update_readable_metadata!(varclass_dict, meta::Dict, varname)
         (:description, VariableDescription),
         (:unit, VariableUnit),
         (:bounds, VariableBounds),
-        (:noise, VariableNoiseType),
         (:input, VariableInput),
         (:output, VariableOutput),
         (:irreducible, VariableIrreducible),

src/variables.jl

@@ -10,7 +10,6 @@ struct VariableUnit end
 Symbolic metadata key for storing the type of connector that a variable is.
 """
 struct VariableConnectType end
-struct VariableNoiseType end
 """
     $TYPEDEF