FIX: Ensure post_created event fires even if topic_created event hooks have exceptions (#38146)

Currently, if `on(:topic_created)` has an error, all subsequent triggers
like `on(:post_created)` would not be triggered. 😱

This PR ensures post created registered event hooks will also trigger
even if the topic created ones fail. Events being rescued are outside of
topic and post creation transactions.

lib/post_creator.rb

@@ -266,8 +266,17 @@ class PostCreator
   end
 
   def trigger_after_events
-    DiscourseEvent.trigger(:topic_created, @post.topic, @opts, @user) unless @opts[:topic_id]
-    DiscourseEvent.trigger(:post_created, @post, @opts, @user)
+    begin
+      DiscourseEvent.trigger(:topic_created, @post.topic, @opts, @user) unless @opts[:topic_id]
+    rescue => e
+      Discourse.warn_exception(e, message: "Error in 'topic_created' event handler")
+    end
+
+    begin
+      DiscourseEvent.trigger(:post_created, @post, @opts, @user)
+    rescue => e
+      Discourse.warn_exception(e, message: "Error in 'post_created' event handler")
+    end
   end
 
   def self.track_post_stats

spec/lib/post_creator_spec.rb

@@ -1653,6 +1653,21 @@ RSpec.describe PostCreator do
       expect(@posts_created).to eq(1)
       expect(@topics_created).to eq(0)
     end
+
+    it "fires post_created even when topic_created handler raises" do
+      bad_handler = proc { raise "topic_created boom" }
+      DiscourseEvent.on(:topic_created, &bad_handler)
+
+      PostCreator.new(
+        user,
+        raw: "this is the new content for my topic",
+        title: "this is my new topic title",
+      ).create
+
+      expect(@posts_created).to eq(1)
+    ensure
+      DiscourseEvent.off(:topic_created, &bad_handler)
+    end
   end
 
   describe "staged users" do