fix(users): Only use lowercase letters in emails

Currently uppercase letters in emails are being using at it is. Ideally we should convert them to lowercase before performing any DB operations with it.
<think>
PR Context:
- Title: feat(users): Convert emails to lowercase from requests
- Merged: 2024-11-20T13:41:03Z
- Files changed: 1 files
- Commits: 2 commits

Implementation approach:
## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [x] Bugfix
- [ ] New feature
- [ ] Enhancement
- [ ] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
<!-- Describe your changes in detail -->
This PR changes will convert emails from request to lowercase before performing any DB operations.

### Additional Changes

- [ ] This PR modifies the API contract
- [ ] This PR modifies the database schema
- [ ] This PR modifies applica
</think>

To implement this, you'll need to modify:


**Detailed Implementation:**


**Commit 1:** feat(users): Convert emails to lowercase from requests (#6601)
Files to modify:


**crates/router/src/types/domain/user.rs**
  Modify existing code
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