Resolve SAST report in MR widget is not rendering list of `all` issues

What does this MR do?

1. Renders show all button for sast and dependency scanning
2. Improves v-if to render issues
3. Fixes padding in scroll by styling the parent element to a max height

Screenshots (if relevant)

Screen_Recording_2018-04-13_at_03.38_PM

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• EE specific content should be in the top level /ee folder
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together

What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/5664 Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/45352