Polish Jira issue fields UI

As suggested by designs in #332280 (closed), the Jira issue fields are reordered, some of the spacing between the fields and labels have been changed, and some elements should be indented to show proper hierarchy.

Note: We should also remove the page-title from the integration title to make it bigger than the section heading Connection details.

Current	Proposal

Proposal

• Use an H2 with the title and mb-4 classes for the integration heading. This would be consistent with an issue or merge request view.

Design source

✏ Figma project