Check for unused pyright: ignore and differentiate from mypy ignores (#9397)

pyrightconfig.testcases.json

@@ -5,6 +5,9 @@
         "test_cases",
     ],
     "typeCheckingMode": "strict",
+    // Using unspecific "type ignore" comments in test_cases.
+    // See https://github.com/python/typeshed/pull/8083
+    "enableTypeIgnoreComments": true,
     "reportPropertyTypeMismatch": "error",
     "reportUnnecessaryTypeIgnoreComment": "error",
     "reportMissingModuleSource": "none",