PR Summary

Python 3 always passes UTF8 encoded strings, so just use that directly
instead of specifying the encoding later.

replaces #21756 because the autorelease semantics was already changed in another PR.

PR Checklist

Tests and Styling

• [N/A] Has pytest style unit tests (and pytest passes).
• [N/A] Is Flake 8 compliant (install flake8-docstrings and run flake8 --docstring-convention=all).

Documentation

• New features are documented, with examples if plot related.
• New features have an entry in doc/users/next_whats_new/ (follow instructions in README.rst there).
• API changes documented in doc/api/next_api_changes/ (follow instructions in README.rst there).
• Documentation is sphinx and numpydoc compliant (the docs should build without error).