Schedule rule component for agents for execution policy

What does this MR do and why?

Describe in detail what your merge request does and why.

This MR resolves #367278 (closed)

It add agent option for schedule rule component. According to this documentation

Screenshots or screen recordings

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action	video
agent selection	cluster
toggle name	toggle_name
save	save

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(:scan_execution_rule_mode)

2. Go to URL/root/PROJECT_ID/-/security/policies
3. Create new policy
4. Select Scan execution policy and click Select policy

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #359886 (closed)