Fix a typo in Admin: intergration -> integration

CE backport: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/23050

What does this MR do?

This is a reopening of https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/6379.

This fixes a typo in Elastic admin page: intergration -> integration.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• [-] Documentation created/updated
• [-] Tests added for this feature/bug
• 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.
• EE specific content should be in the top level /ee folder
• [-] For a paid feature, have we considered GitLab.com plans, how it works for groups, and is there a design for promoting it to users who aren't on the correct plan?