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

[renovate]

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

Compare Source

============

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 <https://t.me/pythontelegrambotchannel>_.

New Features

• Full Support for Bot API 7.10 (:pr:4461 closes :issue:4459, :pr:4460, :pr:4463 by aelkheir <https://github.com/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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Configuration

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