Update job form layout

What does this MR do and why?

This MR is a part of larger effort for Add a page for retrying a CI job with new input... (#547649 - closed). It updates the job details page so that the job form is separated from the empty state. The sidebar should not be visible in a job form state.

Together with this (in a separate commit), I fixed some linter issues:

• Changed event names from camelCase to kebab-case
• Added emits declarations

References

• Add a page for retrying a CI job with new input... (#547649 - closed)

Screenshots or screen recordings

Before	After

How to set up and validate locally

Manual job without log

1. Create a manual job in .gitlab-ci.yml:

   manual_job:
     stage: test
     script: echo "test"
     when: manual

2. Navigate to the job details page
3. Verify the manual variables form displays correctly
4. Verify you can run the job with variables

Retry with modified variables

1. Navigate to any completed job
2. Click the retry dropdown in the sidebar
3. Select "Run again with modified CI/CD variables"
4. Verify the form appears and sidebar hides
5. Click "Cancel" to return to normal view
6. Verify sidebar reappears

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #547649 (closed)