[Fleet]: Confirmation flyout shows blank when all the policies are removed from the shared integration.

Kibana Build details:

VERSION: 8.16.0-SNAPSHOT
BUILD: 79269
COMMIT: 574ec2fc5f383da6bff0d506cc6ab76803119dae

Preconditions:

1. 8.16.0-SNAPSHOT Kibana cloud environment should be available.
2. Shared integration should be installed in various policies.
3. An agent should be installed.

Steps to reproduce:

1. Navigate to Fleet>Agent policies tab.
2. Select policy with which agent is installed and shared integration is there.
3. Edit shared integration.
4. Remove all the agent policies.
5. Observe message in confirmation flyout: Fleet has detected that the selected agent policies, , are already in use by some of your agents. As a result of this action, Fleet will deploy updates to all agents that use these policies.

Expected Result: Confirmation flyout should show appropriate message when all the policies are removed from the shared integration.

Screen Recording:

https://github.com/user-attachments/assets/7f5f2307-5295-4e71-9f04-f1ae585ed11c

Feature: https://github.com/elastic/kibana/issues/75867