[BUG] ProphetModel doesn't work with cap and floor regressors

[julia-shenshina]

🐛 Bug Report

I try to run a ProphetModel with logistic growth and cap and floor in my TSDataset and meet an error.

Notes: cap and floor regressors cause an error with all the growth types

Moreover, there is a test that contains smth about cap and floor (in outdated format) but actually does not check logistic trend.

Expected behavior

Logistic growth works correctly if cap/floor are given in TSDataset.

How To Reproduce

Code

import pandas as pd
from etna.datasets import TSDataset, generate_periodic_df
from etna.models import ProphetModel
from etna.pipeline import Pipeline

df = generate_periodic_df(start_time="2020-01-01", periods=100, period=5)

df_exog = pd.DataFrame({"timestamp": pd.date_range("2020-01-01", periods=150)})
df_exog["segment"] = "segment_0"
df_exog["cap"] = 10
df_exog["floor"] = -10

wide_df = TSDataset.to_dataset(df)
wide_df_exog = TSDataset.to_dataset(df_exog)
ts = TSDataset(wide_df, freq="D", df_exog=wide_df_exog, known_future=["cap", "floor"])

model = ProphetModel(growth="logistic",)
pipeline = Pipeline(model=model, transforms=[], horizon=14)

pipeline.fit(ts)

Error

.../lib/python3.8/site-packages/prophet/forecaster.py:219, in Prophet.validate_column_name(self, name, check_holidays, check_seasonalities, check_regressors)
    216 reserved_names.extend([
    217     'ds', 'y', 'cap', 'floor', 'y_scaled', 'cap_scaled'])
    218 if name in reserved_names:
--> 219     raise ValueError(
    220         'Name {name!r} is reserved.'.format(name=name)
    221     )
    222 if (check_holidays and self.holidays is not None and
    223         name in self.holidays['holiday'].unique()):
    224     raise ValueError(
    225         'Name {name!r} already used for a holiday.'.format(name=name)
    226     )

ValueError: Name 'cap' is reserved.

Environment

No response

Additional context

No response

Checklist

• Bug appears at the latest library version