Branch exceptions additional options

Description

This is a follow-up of this conversation.

When the user opens the dropdown with branch exceptions for Project A, the dropdown contains only the branches of Project A.

We need to find a way for the user to add any branch of any project linked to security project

Design

Figma dev mode link: https://www.figma.com/file/PxITlQcMbvWTMbhM1ghcwv/policy-Small-design?type=design&node-id=1458%3A20602&mode=dev