use to_unicode in escape_char

[niccokunzmann]

escape_char in icalendar.parser should also accept bytes.

• Please follow the development setup: https://icalendar.readthedocs.io/en/stable/contribute/development.html
• Please use to_unicode before doing the replacements
• add a test that checks that bytes work

_escape_char is annotated to accept bytes, but the current replacement chain uses str patterns/replacements, which will raise TypeError if text is actually bytes. Either add a bytes branch (similar to _unescape_char) or restrict the signature/validation to str only so the type hints match runtime behavior.

Originally posted by @Copilot in #1222

[mackarovak]

Hello, can I do it?

[niccokunzmann]

Hi @mackarovak welcome! @Alm0stSurely started a PR for this which solves this. Would you like to do #1230?