Fix issue with federated inventories when relaunch a single child job

[cigamit]

Fixes an issue where the child job was re-inheriting the parent inventory when relaunching.

[Copilot]

Pull request overview

This PR addresses a relaunch regression for workflow child jobs created from federated inventories, where relaunching a single child job could incorrectly re-enter federated workflow creation and/or re-inherit the parent (federated) inventory instead of keeping the child’s effective inventory.

Changes:

• Ensure Job.copy_unified_job() bypasses federated job-template handling on relaunch and preserves the job’s inventory_id.
• Add a functional model test covering relaunch of a federated-workflow child job to ensure it remains a Job and retains inventory/IG routing cache.
• Add a functional API regression test ensuring relaunch works for a job that was spawned as part of a sliced workflow job.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
awx/main/tests/functional/models/test_job.py	Adds a regression test ensuring relaunching a federated workflow child job does not recreate a workflow and preserves inventory/instance group routing cache.
awx/main/tests/functional/api/test_job.py	Adds an API-level relaunch regression test for a job spawned from a sliced workflow job.
awx/main/models/jobs.py	Updates Job.copy_unified_job() to prevent federation logic on relaunch and to eagerly preserve inventory_id (plus existing slice fields).