feat(http-utils): add HTTP 202 Accepted response helper

[slitviachenko]

Please ensure your pull request adheres to the following guidelines:

• make sure to link the related issues in this description
• when merging / squashing, make sure the fixed issue references are visible in the commits, for easy compilation of release notes

Related Issues

https://jira.corp.adobe.com/browse/SITES-31201

Adds a new accepted() function to the HTTP utilities to support HTTP 202 Accepted responses. This status code is commonly used for asynchronous operations where the request has been accepted for processing but the processing has not been completed.

Changes:

• Added accepted() function to create 202 responses
• Added TypeScript type declaration for the new function
• Added unit tests to verify the function behavior

The function follows the same pattern as other response helpers like created() and ok(), providing a consistent API for creating HTTP responses.

[github-actions]

This PR will trigger a minor release when merged.