FEATURE: Count only approved flagged posts in user pages (#22799)

FEATURE: Only approved flags for post counters

* Why was this change necessary?
The counters for flagged posts in the user's profile and user index from
the admin view include flags that were rejected, ignored or pending
review. This introduces unnecessary noise. Also the flagged posts
counter in the user's profile includes custom flags which add further
noise to this signal.

* How does it address the problem?

* Modifying User#flags_received_count to return posts with only approved
  standard flags
* Refactoring User#number_of_flagged_posts to alias to
  User#flags_received_count
* Updating the flagged post staff counter hyperlink to navigate to a
  filtered view of that user's approved flagged posts to maintain
  consistency with the counter
* Adding system tests for the profile page to cover the flagged posts
  staff counter

spec/models/user_spec.rb

@@ -2002,16 +2002,43 @@ RSpec.describe User do
     end
 
     describe "#number_of_flagged_posts" do
-      it "counts flagged posts from the user" do
-        Fabricate(:reviewable_flagged_post, target_created_by: user)
+      fab!(:admin) { Fabricate(:admin) }
 
-        expect(user.number_of_flagged_posts).to eq(1)
+      it "counts only approved standard flagged posts from the user" do
+        %i[disagree ignore delete_and_ignore].each do |review_action|
+          PostActionCreator
+            .off_topic(admin, Fabricate(:post, user: user))
+            .reviewable
+            .perform(admin, review_action)
+        end
+        %i[agree_and_keep delete_and_agree].each do |approval_action|
+          PostActionCreator
+            .off_topic(admin, Fabricate(:post, user: user))
+            .reviewable
+            .perform(admin, approval_action)
+        end
+
+        expect(user.number_of_flagged_posts).to eq 2
+      end
+
+      it "ignores custom flags from the user" do
+        PostActionCreator
+          .notify_moderators(admin, Fabricate(:post, user: user))
+          .reviewable
+          .perform(admin, :agree_and_keep)
+        expect(user.number_of_flagged_posts).to be_zero
       end
 
       it "ignores flagged posts from another user" do
-        Fabricate(:reviewable_flagged_post, target_created_by: Fabricate(:user))
+        other_user = Fabricate(:user)
+        %i[disagree ignore delete_and_ignore agree_and_keep].each do |review_action|
+          PostActionCreator
+            .off_topic(admin, Fabricate(:post, user: other_user))
+            .reviewable
+            .perform(admin, review_action)
+        end
 
-        expect(user.number_of_flagged_posts).to eq(0)
+        expect(user.number_of_flagged_posts).to be_zero
       end
     end
   end