Asynchronously call method

What does this MR do and why?

Asynchronously call method

• the method is async, so it needs to be called that way
• follow up from !164268 (comment 2102080796)

Changelog: changed

EE: true

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

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Before	After
	No visual change

How to set up and validate locally

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

1. Upload a GitLab Ultimate license
2. Navigate to a new project/group => Secure => Policies => New policy => Pipeline execution project => Create a policy
3. Verify the user is navigated to the newly created security policy project with an MR
4. Navigate to the new project/group => Secure => Policies => New policy => Pipeline execution project => Create a policy
5. Verify the user is navigated to the security policy project with an MR
6. Navigate to the new project/group => Secure => Policies => Edit policy project => Remove the linked project
7. Navigate to the new project/group => Secure => Policies => New policy => Pipeline execution project => Create a policy
8. Verify the error appears and a user can still take actions on the page
9. Repeat the steps for every policy type
10. Enable the ff echo "Feature.enable(:security_policies_project_background_worker)" | rails c
11. Verify the steps above work for every policy type

Related to #464329 (closed)