[ci] Restore mypy checks (#2128)

## Description

Fixed in https://github.com/robotpy/mostrobotpy/pull/191. Closes #1968.

## Meta

Merge checklist:
- [x] Pull Request title is [short, imperative
summary](https://cbea.ms/git-commit/) of proposed changes
- [x] The description documents the _what_ and _why_
- [ ] If this PR changes behavior or adds a feature, user documentation
is updated
- [ ] If this PR touches photon-serde, all messages have been
regenerated and hashes have not changed unexpectedly
- [ ] If this PR touches configuration, this is backwards compatible
with settings back to v2025.3.2
- [ ] If this PR touches pipeline settings or anything related to data
exchange, the frontend typing is updated
- [ ] If this PR addresses a bug, a regression test for it is added

.github/workflows/python.yml

@@ -42,14 +42,12 @@ jobs:
             pip install --no-cache-dir dist/*.whl
             pytest
 
-      # Disable due to robotpy issue. See
-      # https://github.com/PhotonVision/photonvision/issues/1968
-      # - name: Run mypy type checking
-      #   uses: liskin/gh-problem-matcher-wrap@v3
-      #   with:
-      #     linters: mypy
-      #     run: |
-      #       mypy --show-column-numbers --config-file photon-lib/py/pyproject.toml photon-lib
+      - name: Run mypy type checking
+        uses: liskin/gh-problem-matcher-wrap@v3
+        with:
+          linters: mypy
+          run: |
+            mypy --show-column-numbers --config-file photon-lib/py/pyproject.toml photon-lib
 
       - name: Upload artifacts
         uses: actions/upload-artifact@master