Clarify asset sharing privacy in bug report template

[kaggle-agent]

Summary

• Reworded the "Share Your Assets" section in the bug report issue template to clearly communicate that sharing notebooks/assets with [email protected] is confidential — only the Kaggle support team can view them, and they will not be shared publicly or used for anything other than troubleshooting.
• Made it clear that without sharing assets, the team cannot debug the issue and it may be closed.
• Changed the "Shared Asset Links" field from optional to required to ensure users provide the necessary information for debugging.

Context

Addresses feedback from #122 where a user was hesitant to share their notebooks. The previous template wording didn't explicitly reassure users about confidentiality or explain that sharing is essential for the support team to help.

Changes

.github/ISSUE_TEMPLATE/bug_report.yml:

• Added a heading with a lock icon: "Share Your Kaggle Assets (Required for Debugging)"
• Added explicit privacy/confidentiality reassurance
• Added clear statement that issues without shared assets cannot be debugged and may be closed
• Changed the field description to reiterate confidentiality
• Changed required: false → required: true for the shared asset links field

Test plan

• Verify the updated template renders correctly by navigating to "New Issue" on the repo
• Confirm the "Shared Asset Links" field is now required
• Confirm the privacy language is clear and visible