Adds horizontal scrolling to network-graph

What does this MR do?

Adds horizontal scrolling to network graph

Are there points in the code the reviewer needs to double check?

• Check if adding horizontal scroll will render the graph on page load as required or push it to top left corner

Why was this MR needed?

• To solve https://gitlab.com/gitlab-org/gitlab-ce/issues/24485 by adding horizontal scrolling

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #24485 (moved)