simplify expiry notification lookups

[havetisyan]

Description

we're addressing 2 issues with this simplification:
a) bug fix: with consolidated email where we only generate notifications once a day, it conflicts with metric notifications which also uses the same attribute and if we generate a metric notification, we might skip the email notification. So now we just use the same list of expired members to generate both email and metric notifications

b) remove the logic where the member has both expiration and review reminder options enabled, start notifications with the review reminder date. most of the users unknowingly set both to the same value and end up with no notifications. Now, that we're generating consolidated notifications, the issue with getting too many emails a day is no longer an issue so no need for extra logic.

Contribution Checklist:

• The pull request does not introduce any breaking changes
• I have read the contribution guidelines.
• Create an issue and link to the pull request.

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