chore(deps): update dependency python-telegram-bot to v21.6

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
python-telegram-bot (changelog)	==21.5 -> ==21.6

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Release Notes

python-telegram-bot/python-telegram-bot (python-telegram-bot)

### [`v21.6`](https://redirect.github.com/python-telegram-bot/python-telegram-bot/blob/HEAD/CHANGES.rst#Version-216) [Compare Source](https://redirect.github.com/python-telegram-bot/python-telegram-bot/compare/v21.5...v21.6) \============ *Released 2024-09-19* This is the technical changelog for version 21.6. More elaborate release notes can be found in the news channel `@pythontelegrambotchannel `\_. ## New Features - Full Support for Bot API 7.10 (:pr:`4461` closes :issue:`4459`, :pr:`4460`, :pr:`4463` by `aelkheir `\_, :pr:`4464`) - Add Parameter `httpx_kwargs` to `HTTPXRequest` (:pr:`4451` closes :issue:`4424`) ## Minor Changes - Improve Type Completeness (:pr:`4466`) ## Internal Changes - Update Python 3.13 Test Suite to RC2 (:pr:`4471`) - Enforce the `offline_bot` Fixture in `Test*WithoutRequest` (:pr:`4465`) - Make Tests for `telegram.ext` Independent of Networking (:pr:`4454`) - Rename Testing Base Classes (:pr:`4453`) ## Dependency Updates - Bump `pytest` from 8.3.2 to 8.3.3 (:pr:`4475`)

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