chore(deps): update mypy requirement from ==1.11.* to ==1.15.*

Updates the requirements on [mypy](https://github.com/python/mypy) to permit the latest version.
- [Changelog](https://github.com/python/mypy/blob/master/CHANGELOG.md)
- [Commits](python/mypy@v1.11...v1.15.0)

---
updated-dependencies:
- dependency-name: mypy
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements-testing.txt

@@ -6,6 +6,6 @@ pytest-timeout == 2.3.*
 pytest-xdist == 3.6.*
 black == 25.*
 ruff == 0.11.*
-mypy == 1.11.*
+mypy == 1.15.*
 psutil == 7.0.*
 types-PyYAML ~= 6.0