fix: disable root path check when serve is false

[nimesh0505]

Summary

This MR addresses the issue where the checkRootPathForErrors function still requires a valid path to root even when serve: false is set.

Changes

• Disabled checkRootPathForErrors when serve: false.
• Added a unit test to confirm that the root path check is bypassed when serve: false.

Tests

• Added a test in test/static.js to verify that checkRootPathForErrors is not called when serve: false.

This fix allows users to use the sendFile decorator without needing to serve static files, as requested.

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[Uzlopak]

Imho this PR does not take in account, that if no general root path is defined, that rootPath parameter of sendFile becomes mandatory.

fastify-static/index.js

Line 84 in 39e89ea

root || sendOptions.root,

[Uzlopak]

why closing so fast? You can do it! :)

[nimesh0505]

@Uzlopak Here is the PR 😅