sktime: [BUG] Auto-ETS parameter setting not working

Describe the bug Want to set auto=True, damped_trend=True, seasonal= None and bound={damping_bound:(0,0.5)} for Auto-ETS–>

To Reproduce import sktime import pandas as pd import numpy sa np import statsmodel def model_training(y_train):

    model_fcst = AutoETS(auto=True, additive_only=True, sp=12, trend='add', damped_trend=True,
                     allow_multiplicative_trend=False, bounds= {damping_bound:(0,0.5)}, error='add',
                      n_jobs=-1)
    model_fcst.fit(y_train)
    return model_fcst

import sktime
import pandas as pd
import numpy sa np
import statsmodel
def model_training(y_train):

        model_fcst = AutoETS(auto=True, additive_only=True, sp=12, trend='add', damped_trend=True,
                         allow_multiplicative_trend=False, bounds= {damping_bound:(0,0.5)}, error='add',
                          n_jobs=-1)
        model_fcst.fit(y_train)
        return model_fcst```

**Expected behavior**

I get the following error:
Arguments: (ValueError('Invalid key: smoothing_seasonal in bounds dictionary'),). It basically doesn't allow me to set auto=True and yet manually specify the damping_bounds range


**Versions**

sktime 0.13.2, python 3.9
Even tried on a different environment with sktime 0.22 and python 3.11

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