Fix stale data for main light directional cookie.

[eh-unity]

Purpose of this PR

Fix usage of stale data for main light cookie when only additional lights cookie(s) are active.
Backport of: 5828

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Testing status

Quick manual testing.

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Comments to reviewers

Notes for the reviewers you have assigned.

[github-actions]

Hi! This comment will help you figure out which jobs to run before merging your PR. The suggestions are dynamic based on what files you have changed.
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URP
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[simon-engelbrecht-soerensen]

Looks good.

[eh-unity]

Test failures are not related to light-cookies. This PR only touches light cookie code.