UI improvement of Admin Dashboard top page

What does this MR do?

Improves UI of Admin Dashboard top page to utilize an extra space for the main target objects (project, group, user names) and to remove str-truncated-60 class from app/views/admin/dashboard/index.html.haml as part of #326634 (closed).

Screenshots (strongly suggested)

before	after

Other cases

PC (after this change)

mobile (after this change)

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have not included a changelog entry because it is developer-facing change.
• [n/a] Documentation (if required)
• Code review guidelines
• [n/a] Merge request performance guidelines
• Style guides
• [n/a] Database guides
• Separation of EE specific content

Availability and Testing

• [-] Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Closes #326635 (closed)