Add e2e test for design management

What does this MR do?

Adds an e2e test for design management

• Includes new QA selectors (and removing some unused ones).
• Gives Issue a default title.
• Allows click_element to accept a text param

Closes gitlab-org/quality/testcases#189 (closed)

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content