Handle window resize event to re-render Roadmap

What does this MR do?

Fixes a ~bug where window resize didn't cause Roadmap render to update. This bug was introduced after migrating Roadmap app to Vuex as a part of #9831 (closed).

Conformity

• Code review guidelines
• Merge request performance guidelines
• Style guides
• Separation of EE specific content
• Review and add/update tests for this feature/bug.
• Tested in all supported browsers

Closes #10898 (closed)