Fix rbac ServiceAccount imagePullSecrets template.

Problem: NGF fails to deploy with NGINX+ because of the rbac ServiceAccount imagePullSecrets template error.

Solution: Fix the spacing which moves imagePullSecrets from being in the ServiceAccount's metadata to its own field.

Testing: Created Kubernetes secret and Docker Config Secret, then deployed NGF with NGINX+ and saw that the error was no longer there.

Closes #1952

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• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
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Release notes

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please add a brief note that summarizes the change.

Fix rbac ServiceAccount imagePullSecrets template which caused errors when running NGF with NGINX+