使用sha256代替MD5算法

[cryptochecktool]

What type of PR is this?
/kind feature
/kind improvement
What this PR does / why we need it:
本次PR对系统中用于电子邮件哈希的算法进行了升级。原先使用的是MD5算法，现在替换为了更安全的SHA-256算法。这一变更提高了数据的安全性，降低了电子邮件被破解的风险。
Which issue(s) this PR fixes:
未指定具体问题编号，但解决了潜在的安全隐患。
Special notes for your reviewer:
在替换哈希算法的过程中，我已经确保了代码的兼容性和性能。建议审查者在合并前进行全面的测试，以确保新算法的正确性和系统的稳定性。
Does this PR introduce a user-facing change?

action required: 由于更换了电子邮件哈希算法，对于现有用户，系统将重新生成基于SHA-256算法的哈希值。请注意，这一变更可能会对评论的email的hash重新生成。

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

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

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