Fix error in GitHub integration when author is missing

[garrrikkotua]

Changes proposed ✍️

What

🤖 Generated by Copilot at 2e5e96e

Fixed a bug in GithubIntegrationService that caused crashes when handling some GitHub pull request review events. Used optional chaining operators to safely access properties of webhook event objects.
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🤖 Generated by Copilot at 2e5e96e

?. operator
avoids serverless crashes
autumn bug fixing

Why

How

🤖 Generated by Copilot at 2e5e96e

• Fix serverless function crash when processing some GitHub pull request review events by using optional chaining operators to access properties of potentially undefined or null objects (link)

Checklist ✅

• Label appropriately with Feature, Improvement, or Bug.
• Add screehshots to the PR description for relevant FE changes
• New backend functionality has been unit-tested.
• API documentation has been updated (if necessary) (see docs on API documentation).
• Quality standards are met.