Remove vue from main.bundle.js

What does this MR do?

While removing code from global scope we added vue into the main.bundle.js file.

This MR reverts that change to the way it was before: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/12232/diffs#87d24632acf1e2ae7b28c60e20d15798f58b0f0c_15_11

Does this MR meet the acceptance criteria?

• Tests
  • 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 #34017 (closed)