Repo-Review: MY105: MyPy enables redundant-expr

Must have "redundant-expr" in enable_error_code = [...]. This helps
catch useless lines of code, like checking the same condition twice.

pyproject.toml

@@ -130,6 +130,7 @@ warn_redundant_casts = true
 warn_unused_ignores = true
 enable_error_code = [
     "ignore-without-code",
+    "redundant-expr",
 ]
 
 [tool.pytest.ini_options]