[BUG] Add load_regression encoding parameter

[Cyril-Meyer]

Reference Issues/PRs

Fixes #3086

What does this implement/fix? Explain your changes.

Add encoding="utf-8" parameter to load_from_ts_file.

def load_from_ts_file(
    full_file_path_and_name,
    replace_missing_vals_with="NaN",
    return_meta_data=False,
    return_type="auto",
    encoding="utf-8"
):

This makes no changes for 99% of usages, but when a .ts file is not UTF-8 encoded, user can specify its encoding.
Example of fixed situation :

import aeon.datasets
x, y = aeon.datasets.load_from_ts_file('K:/Monash_UEA_UCR_Regression_Archive/BIDMC32SpO2/BIDMC32SpO2_TRAIN.ts', encoding='cp1252')

Does your contribution introduce a new dependency? If yes, which one?

No.

Any other comments?

No.

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[Cyril-Meyer]

As said in the issue, this PR do not add tests for this, but I do not think its necessary to add a non utf-8 dataset to the data folder just for this cases.