fix #374 - fix voucher request reminder process

[hugosolar]

Fixes #374

Description

Fixed a bug that doesn't send the number of days passed since the last user state update, because of that, the reminder emails were never sent.

Checklist

• My pull request has a descriptive title (not a vague title like Update index.md).
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• I added tests for the changes I made (if applicable).
• I added or updated documentation (if applicable).
• I tried running the project locally and verified that there are no
  visible errors.

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