fix(ai-help): enhance issue reporting

[caugner]

Summary

Problem

There were two problems with issue reporting:

1. The first question was used as the issue title, not the last.
2. Multiple questions were separated with "---" (no line breaks).

Solution

1. Use the last question.
2. Put the questions in an enumerated list instead.

---

How did you test this change?

Ran yarn && yarn dev, opened http://localhost:3000/en-US/plus/ai-help locally, answered multiple questions, and clicked on the "Report an issue with this answer" link.

[caugner]

Self-approval, because the changes are trivial and only affect the issue reporting, not any other aspect of the feature.