Missing error message if the user forgets to add a sequence_key when using PARSynthesizer

[srinify]

Problem Description

If a user tries to run preprocess() or fit() using PARSynthesizer without specifying a sequence_key, they currently get a less useful error:

Expected behavior

We should instead be returning:

SynthesizerInputError: The PARSythesizer is designed for multi-sequence data, identifiable through a sequence key. Your metadata does not include a sequence key.

Additional context

Code to reproduce this error.

from sdv.sequential import PARSynthesizer
from sdv.metadata.single_table import SingleTableMetadata
import pandas as pd

data_json = {
    'transaction_date': ['2024-01-01', '2024-02-01', '2024-03-01', '2024-01-01', '2024-02-01', '2024-03-01'],
    'key': [0, 0, 0, 1, 1, 1]
}

df1 = pd.DataFrame(data_json)
metadata1 = SingleTableMetadata()
metadata1.detect_from_dataframe(df1)

synth1 = PARSynthesizer(metadata1)
synth1.preprocess(df1)