Fix calendar failed run colors

[bobu-putheeckal]

Fixes #66959.

What changed

• Render failed-only Calendar buckets with the failed/red color in Total Runs mode instead of the success/green palette.
• Render buckets containing both successful/running and failed runs as split green/red cells.
• Add focused Calendar scale tests for failed-only and mixed actual Total Runs buckets.

Tests

• npx --yes pnpm@10.25.0 test src/pages/Dag/Calendar/calendarUtils.test.ts
• npx --yes pnpm@10.25.0 exec tsc --p tsconfig.app.json --noEmit
• npx --yes pnpm@10.25.0 exec eslint src/pages/Dag/Calendar/calendarUtils.ts src/pages/Dag/Calendar/calendarUtils.test.ts

[choo121600]

For your other UI-related PRs as well, it would be helpful if you could include before/after screenshots in the PR description.

[bobu-putheeckal]

Added more detail here for the visual change: the affected Calendar Total Runs buckets now render failed-only days with the failed/red palette, and mixed success+failed days with split green/red cells instead of solid success green. I do not have a reliable local backend-rendered Calendar fixture for a true before/after screenshot in this environment, so I kept the verification focused on the color-selection regression tests in calendarUtils.test.ts.

[kaxil]

PR template hasn't been followed on any of your PRs. As such I am closing all your PRs since I see little to no evidence of actual testing and mass PRs to Airflow & other repos.