fix: handoff only if conversation pending (#13882)

# Pull Request Template

## Description

- Skip handoff when the conversation is no longer pending. 
- Fetch conversation status with Conversation.uncached to avoid stale
query cache when checking pending state.

## 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.

Difficult to reproduce locally, but seen a couple of conversations where
bot hands off an extra time or Captain re-generates usually due to a
retry on FaradayTimeoutError but at perform time, the conversation
status is stale so it appears as if Captain responded in an open
conversation.

## 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

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

@@ -138,7 +138,7 @@ class Captain::Conversation::ResponseBuilderJob < ApplicationJob
 
   def handle_error(error)
     log_error(error)
-    process_action('handoff')
+    process_action('handoff') if conversation_pending?
     true
   end
 
@@ -151,7 +151,7 @@ class Captain::Conversation::ResponseBuilderJob < ApplicationJob
   end
 
   def conversation_pending?
-    status = Conversation.where(id: @conversation.id).pick(:status)
+    status = Conversation.uncached { Conversation.where(id: @conversation.id).pick(:status) }
     status == 'pending' || status == Conversation.statuses[:pending]
   end
 end