FOUR-19455: Use constants to handle the Request and Cases status

[rodriquelca]

Issue & Reproduction Steps

Describe the issue this ticket solves and describe how to reproduce the issue (please attach any fixtures used to reproduce the issue).

Solution

• add CaseStatusConstants class to manage case status constants

How to Test

run tests php artisan test --filter CaseControllerTest

Related Tickets & Packages

• https://processmaker.atlassian.net/browse/FOUR-19455

Code Review Checklist

• [ ] I have pulled this code locally and tested it on my instance, along with any associated packages.
• [ ] This code adheres to ProcessMaker Coding Guidelines.
• [ ] This code includes a unit test or an E2E test that tests its functionality, or is covered by an existing test.
• [ ] This solution fixes the bug reported in the original ticket.
• [ ] This solution does not alter the expected output of a component in a way that would break existing Processes.
• [ ] This solution does not implement any breaking changes that would invalidate documentation or cause existing Processes to fail.
• [ ] This solution has been tested with enterprise packages that rely on its functionality and does not introduce bugs in those packages.
• [ ] This code does not duplicate functionality that already exists in the framework or in ProcessMaker.
• [ ] This ticket conforms to the PRD associated with this part of ProcessMaker.