socket: implement accept() with syscalls_sys_accept4

[xvuko]

This will allow to deprecate/remove accept syscall.

TASK: RTOS-1289

Description

Motivation and Context

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (refactoring, style fixes, git/CI config, submodule management, no code logic changes)

How Has This Been Tested?

• Already covered by automatic testing.
• New test added: (add PR link here).
• Tested by hand on: (list targets here).

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing linter checks and tests passed.
• My changes generate no new compilation warnings for any of the targets.

Special treatment

• This PR needs additional PRs to work (list the PRs, preferably in merge-order).
• I will merge this PR by myself when appropriate.

[gemini-code-assist]

Code Review

This pull request refactors the accept function to be an inline wrapper around accept4 with a flags value of 0. Feedback suggests that implementing accept as an inline function in the header is inconsistent with other socket wrappers in the library and may introduce portability issues. It is recommended to move the implementation to the source file as a regular function.

[github-actions]

Unit Test Results

10 543 tests   9 881 ✅  55m 53s ⏱️
   649 suites    662 💤
     1 files        0 ❌

Results for commit b590d94.

♻️ This comment has been updated with latest results.