fix(client): implement file body support for native HTTP request builder

[jndlansh]

Summary of Changes

• Fixed a bug in the native HTTP request body builder where file uploads were not supported.

• Implemented file body support in NewRequestBodyBuilderImpl.file(Path, String) using BodyPublishers.ofFile.

• Added validation for file existence and readability, throwing clear exceptions for missing/unreadable files.

• Updated unit tests to cover file upload scenarios and skip unreliable permission tests on Windows.

• This pull request addresses the issue (Bug: Native HTTP NewRequestBuilderImpl builds requests with incorrect URI/body/header semantics #3855 ) where native HTTP client file uploads failed due to an unimplemented method. It solves the problem by providing a robust implementation and proper error handling.

• Added org.junit.jupiter:junit-jupiter as a test dependency for improved unit testing.

Issue: #3855

Suggest Reviewer

@heliocastro @camillem @YianZhao @kairoaraujo ... kindly review my PR.

How To Test?

• Run mvn test -pl clients/http-support to verify all unit tests pass.

• Review the implementation in NewRequestBodyBuilderImpl.java and the test coverage in NewRequestBodyBuilderImplTest.java.

• Test file upload requests via the native HTTP client path to ensure correct behavior and error handling.

Checklist

Must:

• All related issues are referenced in commit messages and in PR