fix: exclude ghost and anonymous user when counting users (#3370)

#### What type of PR is this?

/kind bug

#### What this PR does / why we need it:
后台进行用户数量统计时，排除ghost和anonymousUser

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

Fixes #3349 

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

```release-note
修复仪表盘用户数显示错误问题
```

src/main/java/run/halo/app/core/extension/User.java

@@ -34,6 +34,8 @@ public class User extends AbstractExtension {
 
     public static final String ROLE_NAMES_ANNO = "rbac.authorization.halo.run/role-names";
 
+    public static final String HIDDEN_USER_LABEL = "halo.run/hidden-user";
+
     @Schema(required = true)
     private UserSpec spec;
 

src/main/java/run/halo/app/core/extension/endpoint/StatsEndpoint.java

@@ -1,5 +1,6 @@
 package run.halo.app.core.extension.endpoint;
 
+import static java.lang.Boolean.parseBoolean;
 import static org.springdoc.core.fn.builders.apiresponse.Builder.responseBuilder;
 
 import lombok.Data;
@@ -12,6 +13,7 @@ import reactor.core.publisher.Mono;
 import run.halo.app.core.extension.Counter;
 import run.halo.app.core.extension.User;
 import run.halo.app.core.extension.content.Post;
+import run.halo.app.extension.ExtensionUtil;
 import run.halo.app.extension.ReactiveExtensionClient;
 
 /**
@@ -54,7 +56,11 @@ public class StatsEndpoint implements CustomEndpoint {
                 return stats;
             })
             .flatMap(stats -> client.list(User.class,
-                    user -> user.getMetadata().getDeletionTimestamp() == null,
+                    user -> {
+                        var labels = ExtensionUtil.nullSafeLabels(user);
+                        return user.getMetadata().getDeletionTimestamp() == null
+                            && !parseBoolean(labels.getOrDefault(User.HIDDEN_USER_LABEL, "false"));
+                    },
                     null)
                 .count()
                 .map(count -> {

src/main/resources/extensions/user.yaml

@@ -2,6 +2,8 @@ apiVersion: v1alpha1
 kind: User
 metadata:
   name: anonymousUser
+  labels:
+    halo.run/hidden-user: "true"
   finalizers:
     - system-protection
 spec:
@@ -14,6 +16,8 @@ apiVersion: v1alpha1
 kind: User
 metadata:
   name: ghost
+  labels:
+    halo.run/hidden-user: "true"
   finalizers:
     - system-protection
 spec: