Fix several undefined errors in incoming data in Github integration

[garrrikkotua]

Changes proposed ✍️

What

🤖 Generated by Copilot at 8a12c48

Added optional chaining operators to some expressions in githubIntegrationService.ts and activityTypes.ts to handle missing or undefined fields in GitHub pull request events. Added a truthy check for the domain variable in memberService.ts to prevent errors when finding organizations by email domains.
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🤖 Generated by Copilot at 8a12c48

domain truthy check
avoiding errors in code
autumn of bugs ends

Why

How

🤖 Generated by Copilot at 8a12c48

• Prevent errors when handling GitHub pull request events by adding optional chaining operators to record.actor.login, record.assignee.login, and activity.parent.title expressions in GithubIntegrationService class (link, link, link, link, link, link, link)
• Improve data validation and error handling when finding organizations by email domains by checking the truthiness of domain variable before calling organizationService.findByUrl method in MemberService class (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.