Add Azure Pipelines instructions for running pytest-qt tests with PyQt6 to documentation

[astafan8]

I hope this will be helpful for folks!

without this i've been seeing this fatal error (with python fault handler enabled):

tests/test_gui.py Fatal Python error: Aborted

Current thread 0x00007fde441e9c40 (most recent call first):

  File "/home/vsts/work/1/s/.venv/lib/python3.11/site-packages/_pytest/runner.py", line 126 in runtestprotocol
  File "/home/vsts/work/1/s/.venv/lib/python3.11/site-packages/_pytest/runner.py", line 113 in pytest_runtest_protocol
  File "/home/vsts/work/1/s/.venv/lib/python3.11/site-packages/pluggy/_callers.py", line 103 in _multicall
  File "/home/vsts/work/1/s/.venv/lib/python3.11/site-packages/pluggy/_manager.py", line 120 in _hookexec
  File "/home/vsts/work/1/s/.venv/lib/python3.11/site-packages/pluggy/_hooks.py", line 513 in __call__
  File "/home/vsts/work/1/s/.venv/lib/python3.11/site-packages/_pytest/main.py", line 362 in pytest_runtestloop
  File "/home/vsts/work/1/s/.venv/lib/python3.11/site-packages/pluggy/_callers.py", line 103 in _multicall
  File "/home/vsts/work/1/s/.venv/lib/python3.11/site-packages/pluggy/_manager.py", line 120 in _hookexec
  File "/home/vsts/work/1/s/.venv/lib/python3.11/site-packages/pluggy/_hooks.py", line 513 in __call__
  File "/home/vsts/work/1/s/.venv/lib/python3.11/site-packages/_pytest/main.py", line 337 in _main
  File "/home/vsts/work/1/s/.venv/lib/python3.11/site-packages/_pytest/main.py", line 283 in wrap_session
  File "/home/vsts/work/1/s/.venv/lib/python3.11/site-packages/_pytest/main.py", line 330 in pytest_cmdline_main
  File "/home/vsts/work/1/s/.venv/lib/python3.11/site-packages/pluggy/_callers.py", line 103 in _multicall
  File "/home/vsts/work/1/s/.venv/lib/python3.11/site-packages/pluggy/_manager.py", line 120 in _hookexec
  File "/home/vsts/work/1/s/.venv/lib/python3.11/site-packages/pluggy/_hooks.py", line 513 in __call__
  File "/home/vsts/work/1/s/.venv/lib/python3.11/site-packages/_pytest/config/__init__.py", line 175 in main
  File "/home/vsts/work/1/s/.venv/lib/python3.11/site-packages/_pytest/config/__init__.py", line 201 in console_main
  File "/home/vsts/work/1/s/.venv/bin/pytest", line 10 in <module>

Extension modules: PyQt6.QtCore, PyQt6.QtGui, PyQt6.QtWidgets, PyQt6.QtTest, psutil._psutil_linux, psutil._psutil_posix, numpy._core._multiarray_umath, numpy.linalg._umath_linalg, charset_normalizer.md, requests.packages.charset_normalizer.md, requests.packages.chardet.md (total: 11)

##[error]Bash exited with code '134'.

[nicoddemus]

Awesome, thanks!