[Fleet][Enhancement]: User is not able to search for agent policy when numerous agent policies are available under Add agent & Assign to new agent policy flyouts.

[amolnater-qasource]

Kibana Build details:

VERSION: 8.11.0 BC5
BUILD: 68102
COMMIT: 5a5670321307d3bd6e4417943cb33d80e42d4b90

Host OS: All

Preconditions:

1. 8.11.0 BC5 Kibana cloud environment should be available.
2. An agent should be installed.
3. 20+ agent policies with different names should be created.

Steps to reproduce:

1. Navigate to Fleet>Agents tab.
2. Click add agent flyout and observe user is not able to search for specific agent policy and manually has to select from dropdown.
3. Similarly navigate to agents tab and click assign to new policy.
4. Observe user is again not able to search for specific agent policy and manually has to find and select from dropdown.

Screen Recording:

https://github.com/elastic/kibana/assets/77374876/f25cdc28-9b35-4651-8d91-cca996bdf0a0

Enhancement: User is not able to search for agent policy when numerous agent policies are available under Add agent & Assign to new agent policy flyouts.

• This gets difficult to manually find and then select the agent policy.
• Search bar should be available with the dropdown, to help users find the specific agent policy easily.

[elasticmachine]

Pinging @elastic/fleet (Team:Fleet)

[amolnater-qasource]

@manishgupta-qasource Please review.

[manishgupta-qasource]

Secondary review for this ticket is Done

[kpollich]

This would definitely be a good enhancement. We could refactor this dropdown to use EuiComboBox like we do elsewhere in the UI. I'll leave this on the backlog as a p2 enhancement. Thanks for writing this up!