Update mypy to 1.16.0

Author: sobolevn

requirements-tests.txt

@@ -1,6 +1,6 @@
 # Type checkers that we test our stubs against. These should always
 # be pinned to a specific version to make failure reproducible.
-mypy==1.15.0
+mypy==1.16.0
 pyright==1.1.400
 # pytype can be installed on Windows, but requires building wheels, let's not do that on the CI
 pytype==2024.10.11; platform_system != "Windows" and python_version >= "3.10" and python_version < "3.13"