fix!: memory-backed emptyDirs skip storage reqs

[chernetskyi]

Related Issue(s)

Closes #1365.

Description

Require Requests and Limits for emptyDir policy enforces ephemeral-storage requests and limits on emptyDir volumes even if they are memory-backed. This PR addresses this by making an exception for memory-backed volumes.

The previous exception for emptyDir volumes with sizeLimit set is removed, because sizeLimit does not replace the limits mechanics, only complements it.

Checklist

• I have read the policy contribution guidelines.
• I have added test manifests and resources covering both positive and negative tests that prove this policy works as intended.
• I have added the artifacthub-pkg.yml file and have verified it is complete and correct.