fix: move llm call of captain outside transaction (#13559)

# Pull Request Template

## Description

Please include a summary of the change and issue(s) fixed. Also, mention
relevant motivation, context, and any dependencies that this change
requires.
Fixes:

The LLM call was wrapped in a transaction. This is an anti-pattern and
caused idle-connections which PG eventually terminated with
`PQconsumeInput() FATAL: terminating connection due to
idle-in-transaction timeout`

This resulted in activity messages being missing in some conversations
on captain handoff, failures queueing up for retry and captain
responding long after conversation was marked open/snoozed.

## Type of change

- [x] Bug fix (non-breaking change which fixes an issue)

## How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide
instructions so we can reproduce. Please also list any relevant details
for your test configuration.
locally and specs


## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [x] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

enterprise/app/jobs/captain/conversation/response_builder_job.rb

@@ -13,9 +13,7 @@ class Captain::Conversation::ResponseBuilderJob < ApplicationJob
     if captain_v2_enabled?
       generate_response_with_v2
     else
-      ActiveRecord::Base.transaction do
-        generate_and_process_response
-      end
+      generate_and_process_response
     end
   rescue StandardError => e
     raise e if e.is_a?(ActiveStorage::FileNotFoundError) || e.is_a?(Faraday::BadRequestError)
@@ -44,11 +42,15 @@ class Captain::Conversation::ResponseBuilderJob < ApplicationJob
   end
 
   def process_response
-    return process_action('handoff') if handoff_requested?
-
-    create_messages
-    Rails.logger.info("[CAPTAIN][ResponseBuilderJob] Incrementing response usage for #{account.id}")
-    account.increment_response_usage
+    ActiveRecord::Base.transaction do
+      if handoff_requested?
+        process_action('handoff')
+      else
+        create_messages
+        Rails.logger.info("[CAPTAIN][ResponseBuilderJob] Incrementing response usage for #{account.id}")
+        account.increment_response_usage
+      end
+    end
   end
 
   def collect_previous_messages