Update Call Disposition Time (in ms)

Updating __only__ Call Dispostion option on Conversation Outcome form.

From local Rails server's log:
```
D, [2018-08-02T17:21:53.297271 #23825] DEBUG -- :   SQL (0.4ms)  INSERT INTO `sent_general_call_prompts` (`salesforce_entity_id`, `general_prompt_id`, `created_at`, `updated_at`) VALUES ('0037000000a6o7S', 1, '2018-08-02 10:21:53', '2018-08-02 10:21:53')
D, [2018-08-02T17:21:53.302215 #23825] DEBUG -- :    (3.7ms)  COMMIT
D, [2018-08-02T17:21:53.305102 #23825] DEBUG -- :   UserSetting Load (1.4ms)  SELECT  `user_settings`.* FROM `user_settings` WHERE `user_settings`.`user_id` = 1 AND `user_settings`.`name` = 'show_task_options' LIMIT 1
D, [2018-08-02T17:21:53.307590 #23825] DEBUG -- :    (0.4ms)  BEGIN
D, [2018-08-02T17:21:53.308944 #23825] DEBUG -- :    (0.2ms)  COMMIT
I, [2018-08-02T17:21:54.576765 #23825]  INFO -- : Enqueued UserActionJob (Job ID: 8e150f8a-a08c-4e14-80df-6a3742801fdd) to Sidekiq(default) with arguments: {:user_id=>1, :organization_id=>1, :event=>"API[Create]", :duration=>1}
I, [2018-08-02T17:21:54.577868 #23825]  INFO -- : Enqueued UserActionJob (Job ID: f31d6807-a374-41bc-8147-a77a32c4e8e5) to Sidekiq(default) with arguments: {:user_id=>1, :organization_id=>1, :event=>"Tasks Saved", :duration=>0}
I, [2018-08-02T17:21:54.579324 #23825]  INFO -- : Enqueued UserActionJob (Job ID: 13148465-349a-4213-a2b9-0b32691b80f8) to Sidekiq(default) with arguments: {:user_id=>1, :organization_id=>1, :event=>"Conversations Logged", :duration=>0}
D, [2018-08-02T17:21:54.588577 #23825] DEBUG -- :   SQL (4.1ms)  DELETE FROM `cached_lists` WHERE (entity_id='0037000000a6o7S')
```

Most time consuming:
  1. SQL (4.1ms)  DELETE FROM `cached_lists` WHERE (entity_id='0037000000a6o7S')
  2. INSERT INTO `sent_general_call_prompts` (`salesforce_entity_id`, `general_prompt_id`, `created_at`, `updated_at`) VALUES ('0037000000a6o7S', 1, '2018-08-02 10:21:53', '2018-08-02 10:21:53') (3.7ms)  COMMIT