Fix showing empty block in ci lint

What does this MR do?

When a user does not have a before_script or after_script defined which is fairly common we are showing an empty block which can be a bit confusing to the user.

Before	After

Tested with the following ci job definition

stages:
- prebuild

helper images:
  stage: prebuild
  script:
  - make helper-build helper-docker
  artifacts:
    paths:
    - out/helper-images/
    - dockerfiles/build/binaries/*-windows.exe
    - .gopath/bin
    - .gopath/.ok
    expire_in: 7d

What are the relevant issue numbers?

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• [-] Documentation created/updated via this MR
• [-] Documentation reviewed by technical writer or follow-up review issue created
• [-] Tests added for this feature/bug
• [-] Tested in all supported browsers
• [-] Conforms to the code review guidelines
• [-] Conforms to the merge request performance guidelines
• [-] Conforms to the style guides
• [-] Conforms to the database guides
• [-] Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• Security reports checked/validated by reviewer