revert changes to mypy

Author: parthea

.github/workflows/mypy.yml

@@ -15,7 +15,7 @@ jobs:
     - name: Setup Python
       uses: actions/setup-python@v5
       with:
-        python-version: "3.14"
+        python-version: "3.10"
     - name: Install nox
       run: |
         python -m pip install --upgrade setuptools pip wheel

noxfile.py

@@ -259,7 +259,7 @@ def unit_noextras(session):
     run_unit(session, install_test_extra=False)
 
 
-@nox.session(python=DEFAULT_PYTHON_VERSION)
+@nox.session(python="3.10")
 def mypy(session):
     """Run type checks with mypy."""
     # Editable mode is not compatible with mypy when there are multiple