Standalone modal - fix rendering of request and response sections

What does this MR do and why?

Fix the behaviour of the request/response rendering, so it is aligned with the current modal:

• The request section should not render if there is no method, url or headers data
• The response section should not render if there is no statusCode or headers data

Screenshots or screen recordings

Before	After

How to set up and validate locally

Setup

1. Have the related FF enabled: echo "Feature.enable(:standalone_finding_modal)" | rails c
2. You'll need an EE License
3. You'll need to have runners enabled (See $2408961 for setting up a runner)
4. Import https://gitlab.com/gitlab-examples/security/security-reports
5. Run a pipeline on master

Validation

1. Go to the pipeline's security report tab
2. Set Filter: Tool -> DAST
3. Click on the finding with the title "CWE-16 in" and verify that the request/response section is showing
4. Click on the other DAST findings and verify that the request/response sections are not showing

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #416352 (closed)