Fix the repeat registration with the email already verified

[JohnNiang]

What type of PR is this?

/kind bug
/area core
/milestone 2.20.x

What this PR does / why we need it:

This PR fixes the repeat registration with the email already verified.

Which issue(s) this PR fixes:

Fixes #7308

Does this PR introduce a user-facing change?

修复注册时未验证邮箱是否已被占用的问题

[Copilot]

Pull Request Overview

This PR fixes a bug that allowed repeat registrations with an email that has already been verified by enforcing a check for duplicate verified emails.

• Added a new exception (EmailAlreadyTakenException) to indicate a duplicate verified email.
• Updated the signUp method in UserServiceImpl to verify the email and prevent duplicate registrations.
• Introduced new test coverage in UserServiceImplTest to ensure the fix works correctly.

Reviewed Changes

Copilot reviewed 5 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
application/src/test/java/run/halo/app/core/user/service/impl/UserServiceImplTest.java	Added a test to verify that a duplicate email triggers the EmailAlreadyTakenException.
application/src/main/java/run/halo/app/security/preauth/PreAuthSignUpEndpoint.java	Updated error handling in the sign-up endpoint to properly handle the duplicate email scenario.
application/src/main/java/run/halo/app/infra/exception/EmailAlreadyTakenException.java	Introduced a new exception class to represent the duplicate verified email error.
application/src/main/java/run/halo/app/core/user/service/impl/UserServiceImpl.java	Modified signUp logic to check for duplicate verified emails and set email verification status accordingly; added a helper method checkEmailAlreadyVerified.
api/src/main/java/run/halo/app/core/user/service/UserService.java	Updated interface to include the new checkEmailAlreadyVerified method.

Files not reviewed (2)

• application/src/main/resources/config/i18n/messages.properties: Language not supported
• application/src/main/resources/config/i18n/messages_zh.properties: Language not supported

[sonarqubecloud]

Quality Gate passed

Issues
3 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

Attention: Patch coverage is 68.75000% with 5 lines in your changes missing coverage. Please review.

Project coverage is 57.50%. Comparing base (60c2009) to head (5b05b54).
Report is 8 commits behind head on main.

Files with missing lines	Patch %	Lines
...lo/app/security/preauth/PreAuthSignUpEndpoint.java	0.00%	4 Missing ⚠️
...lo/app/core/user/service/impl/UserServiceImpl.java	87.50%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #7323      +/-   ##
============================================
+ Coverage     57.18%   57.50%   +0.32%     
- Complexity     4066     4100      +34     
============================================
  Files           721      722       +1     
  Lines         24546    24609      +63     
  Branches       1612     1621       +9     
============================================
+ Hits          14036    14151     +115     
+ Misses         9882     9818      -64     
- Partials        628      640      +12     

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[ruibaby]

/lgtm

[f2c-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ruibaby

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