Check email domain is not undefined when assigning orgs

[garrrikkotua]

Changes proposed ✍️

What

🤖 Generated by Copilot at 43876a2

Fixed a bug in member.service.ts that could cause an error when processing invalid emails. Improved the email domain analysis logic for the data sink worker service.
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🤖 Generated by Copilot at 43876a2

isDomainExcluded
Check before calling, avoid
Error in winter

Why

How

🤖 Generated by Copilot at 43876a2

• Fix potential error when email is invalid or does not contain a domain (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.