test(optimizer): add CJS __esModule interop tests

[Copilot]

Ports test coverage from #16437 for CJS modules with __esModule flag to ensure dev/build interop consistency with Rollup.

Changes

• Test dependency: dep-cjs-with-es-module-flag - CommonJS module with __esModule: true
• E2E tests: Static and dynamic import assertions in optimize-deps playground
• Configuration: Added to optimizeDeps.include for prebundling coverage

Context

CJS modules compiled from ESM (via TypeScript, Babel, etc.) set __esModule: true to signal default export behavior. Vite's interop handling must match Rollup's to avoid runtime discrepancies between dev and prod.

Credits: @XiSenao

Warning

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• workers.cloudflare.com
  • Triggering command: /opt/hostedtoolcache/node/24.13.0/x64/bin/node /opt/hostedtoolcache/node/24.13.0/x64/bin/node --conditions node --conditions development --experimental-import-meta-resolve --require /home/REDACTED/work/vite/vite/node_modules/.pnpm/vitest@4.0.18_@types+node@22.19.7/node_modules/vitest/suppress-warnings.cjs /home/REDACTED/work/vite/vite/node_modules/.pnpm/vitest@4.0.18_@types+node@22.19.7/node_modules/vitest/dist/workers/forks.js (dns block)

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• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
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