perf: improve the validation rules for username (#868)

#### What type of PR is this?

/kind improvement

#### What this PR does / why we need it:

优化用户名的校验规则，目前采用 DNS 名称的规则，即：必须以字母（a-z或A-Z）开头，并包含字母数字字符（a-z，A-Z，0-9）和连字符（-）。每一段名称以字母结尾（a-z或A-Z）。名称以点（.）分隔

#### Which issue(s) this PR fixes:

Fixes https://github.com/halo-dev/halo/issues/3239

#### Screenshots:

#### Special notes for your reviewer:

测试方式：

1. 新建用户，检查用户名输入规则是否符合预期。

#### Does this PR introduce a user-facing change?

```release-note
优化 Console 端新建用户时，用户名的校验规则。
```

src/modules/system/users/components/UserEditingModal.vue

@@ -173,7 +173,17 @@ const handleCreateUser = async () => {
               label="用户名"
               type="text"
               name="name"
-              validation="required|alphanumeric|length:0,50"
+              :validation="[
+                ['required'],
+                ['length:0,63'],
+                [
+                  'matches',
+                  /^[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*$/,
+                ],
+              ]"
+              :validation-messages="{
+                matches: '请输入有效的用户名',
+              }"
             ></FormKit>
             <FormKit
               id="displayNameInput"