[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 b365332)

Co-authored-by: Nikita Sobolev <[email protected]>

Author: miss-islington

.github/workflows/mypy.yml

@@ -34,6 +34,7 @@ concurrency:
 jobs:
   mypy:
     strategy:
+      fail-fast: false
       matrix:
         target: [
           "Lib/_pyrepl",