TST(BF workaround): UTF-8 locale causes python 3.8 to segfault during…

… tests, so let's try to go with 3.11

E.g. https://github.com/datalad/datalad/actions/runs/9163111095/job/25239473610?pr=7600

    [gw1] [ 24%] PASSED ../datalad/interface/tests/test_utils.py::test_incorrect_msg_interpolation
    ../datalad/interface/tests/test_utils.py::test_custom_result_renderer
    [gw1] [ 24%] PASSED ../datalad/interface/tests/test_utils.py::test_custom_result_renderer
    ../datalad/interface/tests/test_utils.py::test_custom_result_summary_renderer
    [gw1] [ 24%] PASSED ../datalad/interface/tests/test_utils.py::test_custom_result_summary_renderer
    Fatal Python error: Segmentation fault
    Thread 0x00007f443effe640 (most recent call first):
      File "/tmp/dl-miniconda-wd5q979m/lib/python3.8/threading.py", line 306 in wait
      File "/tmp/dl-miniconda-wd5q979m/lib/python3.8/threading.py", line 558 in wait
      File "/tmp/dl-miniconda-wd5q979m/lib/python3.8/site-packages/tqdm/_monitor.py", line 60 in run
      File "/tmp/dl-miniconda-wd5q979m/lib/python3.8/threading.py", line 932 in _bootstrap_inner
      File "/tmp/dl-miniconda-wd5q979m/lib/python3.8/threading.py", line 890 in _bootstrap

we also then need to adjust _DL_ANNEX_INSTALL_SCENARIO to match version of
python instead of default 3.7

tools/ci/test-jobs.yml

@@ -7,7 +7,7 @@
 - python-version: '3.7'
   extra-envs: {}
 
-- python-version: '3.8'
+- python-version: '3.11'
   # Run all tests in a single whoop here
   # We cannot have empty -A selector, so the one which always will be fulfilled
   extra-envs:
@@ -17,6 +17,7 @@
     # From our testing in that PR seems to have no effect, but kept around
     # since should not hurt.
     LC_ALL: ru_RU.UTF-8
+    _DL_ANNEX_INSTALL_SCENARIO: "miniconda --channel conda-forge --python-match minor --batch git-annex -m conda"
 
 - python-version: '3.9'
   extra-envs: