[7.2.x] Remove done trainings (#10472)

Co-authored-by: Florian Bruhin <[email protected]>

Author: github-actions[bot]

doc/en/index.rst

@@ -2,7 +2,6 @@
 
 .. sidebar:: Next Open Trainings
 
-   - Professionelles Testen für Python mit pytest, part of `enterPy <https://www.enterpy.de/>`__ (German), `October 28th <https://www.enterpy.de/veranstaltung-15409-se-0-professionelles-testen-fuer-python-mit-pytest.html>`__ (sold out) and `November 4th <https://www.enterpy.de/veranstaltung-15557-se-0-professionelles-testen-fuer-python-mit-pytest-zusatztermin.html>`__, online
    - `Professional Testing with Python <https://python-academy.com/courses/python_course_testing.html>`_, via `Python Academy <https://www.python-academy.com/>`_, March 7th to 9th 2023 (3 day in-depth training), Remote and Leipzig, Germany
 
    Also see :doc:`previous talks and blogposts <talks>`.