[Jino-T]

Description

Documents what the ServiceDesk Plus issue tracker connector now sends beyond its built-in fields, on the ServiceDesk Plus connector reference page:

• The Custom Fields step, including setting a mandatory Requester, and how each Vendor Field is shaped for the ServiceDesk Plus v3 API: lookup fields by name, a field.attribute form such as requester.email_id, udf_* user-defined fields, and plain text for anything else.
• When a mapping applies (Creation or Update), and that the built-in fields take precedence on a clash.
• The Ticket Template step, which replaces the request description and falls back to the built-in one if it fails to render.
• That a rejection for a missing mandatory field now names the field in the Integration errors table.

The connector change itself ships in the Pro integrators service in the same release.

Test results

Documentation only. The Markdown source was reviewed; the page was not rendered locally.

Documentation

This PR is the documentation change. English page only, matching recent connector reference updates.

Checklist

• Make sure to rebase your PR against the very latest dev.
• Submit all PRs, features and bug fixes alike, against the dev branch.
• Give a meaningful name to your PR, as it may end up being used in the release notes.
• Your code is Ruff compliant (see ruff.toml).
• Your code is python 3.13 compliant.
• If this is a new feature and not a bug fix, you've included the proper documentation in the docs at https://github.com/DefectDojo/django-DefectDojo/tree/dev/docs as part of this PR.
• Model changes must include the necessary migrations in the dojo/db_migrations folder.
• Add applicable tests to the unit tests.
• Add the proper label to categorize your PR.