fix: missing default values for system settings

[ruibaby]

What type of PR is this?

/kind bug
/area core
/milestone 2.16.x

What this PR does / why we need it:

补充缺失的系统设置默认值。

Does this PR introduce a user-facing change?

修复系统设置未保存导致无法正常注册的问题

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 56.47%. Comparing base (5fdf6c0) to head (e9e00e0).
Report is 226 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #6035      +/-   ##
============================================
- Coverage     56.91%   56.47%   -0.44%     
- Complexity     3319     3541     +222     
============================================
  Files           587      622      +35     
  Lines         18968    20961    +1993     
  Branches       1401     1478      +77     
============================================
+ Hits          10795    11838    +1043     
- Misses         7594     8523     +929     
- Partials        579      600      +21     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[JohnNiang]

/lgtm

/cherrypick release-2.16

[f2c-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: JohnNiang

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [JohnNiang]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[JohnNiang]

/cherrypick release-2.16

[halo-dev-bot]

@JohnNiang: once the present PR merges, I will cherry-pick it on top of release-2.16 in a new PR and assign it to you.

In response to this:

/cherrypick release-2.16

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[halo-dev-bot]

@JohnNiang: new pull request created: #6036

In response to this:

/cherrypick release-2.16

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.