Update validation for multiple approval actions

What does this MR do and why?

Update validation for multiple approval actions

Multiple approvals actions provides new validation format.

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Description	UI
Multiple approval actions	validation.mov

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Enable feature flag:

   Feature.enable(:multiple_approval_actions)

2. Go to Group/Project

3. Secure -> Policies

4. New approval policy

5. Add multiple require actions, set approvers more then 1 for different actions

6. Save policy

Related to #507380 (closed)