[3.13] Use `fail-fast: false` in `mypy.yml` (GH-119297) (#119304)

Use `fail-fast: false` in `mypy.yml` (GH-119297)

See docs about this setting: https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actionsGH-jobsjob_idstrategyfail-fast
(cherry picked from commit b36533290608aed757f6eb16869a679650d32e17)

Co-authored-by: Nikita Sobolev <mail@sobolevn.me>